JP2002269874A - Magnetic head of magnetic recording/reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that an additional space is necessary for installing a pole for adjusting the angle of a tape entering into a magnetic core and also the production cost is increased. SOLUTION: A guide post section 4 which adjusts the entering angle θ of the magnetic tape T with the magnetic core 3 of the magnetic head 1 is provided integrally with a holder 2 on which the magnetic core 3 is installed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus for recording / reproducing information on or erasing information from / on a magnetic tape, and more particularly to a magnetic head used for the magnetic recording / reproducing apparatus.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a conventional magnetic recording / reproducing apparatus of this kind. This magnetic recording / reproducing apparatus includes a vertical pole 101 with which a magnetic tape 100 pulled out from a tape cassette A contacts, a tension pole 102 for adjusting the tension of the magnetic tape 100, and a full-width erasing head for erasing a video / audio signal during recording. 104
, Entrance side guide roller 105, entrance side inclined pole 1
06, and a rotary head cylinder 107 for recording and reproducing video signals.

According to the magnetic recording / reproducing apparatus having such a configuration, the magnetic tape 10 pulled out from the tape cassette A
0 contacts the full width erase head 104 after passing through the vertical pole 101 and the tension pole 102.

In this full width erasing head 104, for example, as shown in FIG.
04A is fixed and held by a holder 104B, and the holder 104B is attached to a base 110. And
The full-width erasing head 104 does not operate at the time of reproduction, but at the time of recording, a magnetic field for erasing is formed by a high-frequency current generated by an oscillation circuit inside the VTR.
Delete all information recorded in.

Usually, in the magnetic tape 100, the magnitude of the tension acting on the magnetic tape 100 to be pulled out from the tape cassette A at the beginning of the drawing and at the end of the drawing is different. To adjust for fluctuations. For this reason, the tension pole 102 is mounted on the main body of the magnetic recording / reproducing apparatus so as to be movable toward the traveling path of the magnetic tape 100, and a spring force is applied.

On the other hand, when the tension of the magnetic tape 100 is adjusted by the tension pole 102, the angle (incident angle) of the tension pole 102 against the magnetic core 104 A of the full-width erase head 104 depends on how the tension tape 102 is biased to the magnetic tape 100. Since it fluctuates, a means for adjusting the angle is required. Therefore, this tension pole 10
There is also known a configuration in which a pole 103 (see FIG. 4) for adjusting the angle of incidence is provided between the head 2 and the full width erase head 104.

However, with such a configuration,
Since the pole 103 must be formed and installed separately from the full-width erasing head 104, it is necessary to secure an extra installation space, and at the same time, the cost is increased.

[0008]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a magnetic head of a magnetic recording / reproducing apparatus capable of suppressing an increase in installation space and reducing manufacturing costs in view of the above-mentioned circumstances. And

[0009]

SUMMARY OF THE INVENTION The present invention relates to a resin holder having an opening for supporting a magnetic core of a magnetic head so as to protrude in the direction of a tape running surface and has a columnar shape having an axis parallel to the axis of the magnetic core. A guide post having a curved surface at least in contact with the tape, and having a length in the axial direction longer than at least the width of the tape, and integrally forming the guide post; The magnetic tape is provided in a positional relationship such that the magnetic tape that contacts the guide post and reaches the magnetic core does not contact the edge of the magnetic core on the tape receiving side.

The radius of curvature of the curved shape of the guide post portion is preferably set smaller than the radius of curvature of the magnetic core at the contact surface with the tape.

Further, the present invention is practically applied to a full-width erasing head which is installed downstream of a tension pole for adjusting the tension of a magnetic tape drawn from a tape cassette in a tape running direction.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 and 2
Indicates a magnetic head of the magnetic recording and reproducing apparatus according to the present invention. The magnetic head 1 of this magnetic recording / reproducing apparatus is a full-width erasing head for erasing a video / audio signal at the time of recording, and includes a holder 2, a magnetic core 3 held by the holder 2, a coil (not shown), Guide post part 4 provided integrally
And so on. In addition, in FIG.
It is a tension pole.

The holder 2 is formed by molding a resin material having appropriate strength and flexibility, for example, PBT (polybutylene terephthalate) or PPS (polyphenylene sulfite). The holder 2 has an opening 2A (see FIG. 2) for mounting the magnetic core 3 in a state where the magnetic core 3 is protruded by a fixed amount in the running surface direction of the magnetic tape T. Further, the holder 2 is formed with a width-direction regulating surface 2B which is located above and below the opening 2A and regulates the vertical position of the magnetic tape T.

The holder 2 is provided with a leg 2C projecting the pin 5 from the lower side, and is inserted into a connector (not shown) provided on the main body side of the magnetic recording / reproducing apparatus for easy electrical connection. You can do it.

The magnetic core 3 is formed of a soft magnetic material, more specifically, a material having high magnetic permeability, low coercive force, high saturation magnetic flux density, and high resistance, such as ferrite, as shown in FIG. A front magnetic core 3A having a gap G using an electrically insulating non-magnetic glass film or the like, and a back magnetic core 3B wound with a winding via a bobbin (not shown). Is held in a state of being sandwiched from above and below.

The guide post 4 adjusts the angle at which the magnetic tape T enters the magnetic core 3 (hereinafter, referred to as the angle of incidence). Is prevented from contacting the edge 3C portion. That is, the guide post portion 4 is substantially columnar having an axis parallel to the axis of the magnetic core 3, at least a surface facing the magnetic tape T has a smooth curved surface shape, and has a length in this axial direction. Has a length W at least larger than the tape width, and is formed integrally with the holder 2 by resin molding.

In particular, the guide post 4 of this embodiment
Is composed of a prism portion having a substantially rectangular cross section and a curved portion having a substantially semicircular cross section provided on the tip end side of the prism portion. That is,
The guide post portion 4 has a curved surface portion at the portion facing the magnetic tape T, and the radius of curvature R1 is smaller than the radius of curvature R2 at the curved surface of the magnetic core 3 contacting the magnetic tape T. (R1 <R2), in other words, it is formed with a larger curvature than the magnetic core 3 side. For example, in this embodiment, R1 = 0.5 mm. In addition, the remaining amount of the magnetic tape T in the tape cassette fluctuates with the winding operation of the magnetic tape, and when the tension fluctuates according to the change of the remaining amount, the magnetic tape T is moved in accordance with the strength of the tension. The guide post 4 may or may not be in contact.

Next, the positional relationship between the magnetic core 3 and the guide post 4 will be described. As shown in FIG. 2, the guide post 4 is separated from the tip 3D of the magnetic core 3, that is, the gap G by a distance D, and the tip 4A of the guide post 4 (FIG. 2). reference)
Is a distance H (for example, more than the tip portion 3D of the magnetic core 3)
(0.5 mm). FIG.
, The angle of incidence θ of the magnetic tape T into the magnetic core 3 is at least 0 ° with the line L parallel to the Y-axis direction.
The angle varies from 0 degree to the maximum angle of incidence θ2 (for example, about 16 °). In particular, by using the guide post portion 4, the angle is changed from 0 degree to the maximum angle of incidence θ1 (for example, 8 °).
Degree). As a result, even if the tension of the magnetic tape fluctuates, the magnetic tape T remains at the edge 3C of the magnetic core 3 (the leading end on the side where the magnetic tape T is taken in).
Can be avoided.

Therefore, according to the magnetic head 1, the guide post portion 4 provided integrally with the holder 2 allows the magnetic head to be moved from the tension pole 6 without the need to separately form the pole by a separate member as in the prior art. The variation in the tape insertion angle θ with respect to the first magnetic core 3 can be suppressed to a slight angle. This effectively prevents the running magnetic tape T from contacting and abrading the edge 3C of the magnetic core 3.

The holder 2 of the present embodiment is formed by molding a resin material, and requires a molding die. In this molding die, a portion corresponding to the guide post portion 4 may be post-processed or a nested die may be provided in the existing molding die of the holder 2 having no guide post portion 4, so that the molding cost is almost all. There is the additional effect of not increasing.

[0021]

According to the present invention, there is provided a resin holder having an opening in which a magnetic core of a magnetic head is mounted so as to protrude in the direction of a tape running surface, and has a columnar shape having an axis parallel to the axis of the magnetic core. At least a contact surface with the tape has a curved surface shape, and a guide post portion having an axial length longer than at least a tape width is integrally formed, and the guide post portion is formed by the guide post. Since the magnetic tape reaching the magnetic core in contact with the portion is provided in a positional relationship such that it does not contact the edge portion of the magnetic core on the tape take-in side, even if the guide post conventionally provided separately was not installed, The angle of entry of the tape can be adjusted, so that the installation space can be reduced and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a magnetic head according to the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is an explanatory diagram showing a running state of a magnetic tape in a magnetic recording / reproducing apparatus provided with a conventional magnetic head.

FIG. 4 is an explanatory diagram showing the installation state of a magnetic head and guide posts in a conventional magnetic recording / reproducing apparatus.

[Explanation of symbols]

 Reference Signs List 1 magnetic head 2 holder 2A opening 3 magnetic core 3C edge (tip on the tape taking-in side) 4 guide post 5 pin G gap T magnetic tape θ1 (There is no regulation in the department)

Claims (3)

[Claims] 1. A magnetic recording / reproducing apparatus comprising: a magnetic head on which a magnetic tape contacts and slides, and records and reproduces information on and from the magnetic tape by using the magnetic head. In a resin holder having an opening for projecting and supporting in the running surface direction, a columnar shape having an axis parallel to the axis of the magnetic core, at least a contact surface with the tape has a curved surface shape, and A guide post having a length in the axial direction longer than at least the tape width is integrally formed and formed, and the guide post is brought into contact with the guide post and a magnetic tape reaching the magnetic core, A magnetic head for a magnetic recording / reproducing apparatus, wherein the magnetic core is provided in a positional relationship so as not to contact an edge portion of the magnetic core on a tape receiving side. 2. The magnetic head according to claim 1, wherein a radius of curvature of the curved shape of the guide post portion is smaller than a radius of curvature of the magnetic core at a contact surface with the tape. And a tension pole for adjusting the tension of the magnetic tape drawn from the tape cassette and reaching the magnetic head, wherein the magnetic head is located downstream of the tension pole in the tape running direction. 3. The magnetic head for a magnetic recording / reproducing apparatus according to claim 1, wherein the magnetic head is a full-width erase head.