JPH0567929U - Cylinder device for magnetic recording / reproducing device - Google Patents

Abstract

(57) [Summary] [Object] To provide a cylinder device of a magnetic recording / reproducing apparatus, which suppresses uneven wear caused by a slight displacement of a tape-shaped magnetic recording medium. [Structure] A rotating upper cylinder 1 and a fixed lower cylinder 2 are provided, the diameter of the upper cylinder 1 is made larger than the diameter of the lower cylinder 2, and a taper portion 3 is provided at the lower end portion of the upper cylinder 1 over the entire circumference. The head window 10 is provided at a part of the lower end of the cylinder.
And the magnetic head 4 is provided in the head window 10, and the tape-shaped magnetic recording medium 9 is provided on a part of the outer peripheral surface of the cylinder.
In a cylinder device of a magnetic recording / reproducing apparatus configured to wind a recording signal track in an oblique direction of the recording medium 9, at least the rear end of the upper cylinder of the magnetic head 4 in the rotational direction during reproduction and The distance from the edge of the opposing head window 10 is set to 0.3 mm or less, and at least the rear corner of the upper cylinder 1 of the head window 10 with respect to the rotational direction during reproduction has a radius of 0.2 mm or more. A cylinder device of a magnetic recording / reproducing device provided as described above.

Description

[Detailed description of the device]

[0010]

[Industrial application]

 The present invention relates to a cylinder device of a magnetic recording / reproducing apparatus which can be used in a digital audio tape recorder, a video tape recorder, and the like.

[0020]

[Prior Art]

 Conventionally, a cylinder device, which is a recording / reproducing portion of a magnetic recording / reproducing device such as a digital audio tape recorder (DAT) or a video tape recorder (VTR), has an upper cylinder 31 that is rotationally driven as shown in FIGS. , A lower cylinder 32 that is fixed and not driven. The lower cylinder 32 has a smaller diameter than the upper cylinder 31, and a plurality of head windows 36 are formed between the upper cylinder 31 and the lower cylinder 32 at regular intervals in the circumferential direction. A magnetic head 34 is attached. A tape-shaped magnetic recording medium 39 is obliquely wound around and abutted on such a cylinder device, and a recording signal track is formed by the head 34 in an oblique direction of the tape-shaped magnetic recording medium 39.

When the flying height of the tape-shaped magnetic recording medium 39 slidingly contacting the circumferential direction of the cylinder device from the circumferential surface of the cylinder was measured, the result as shown in FIG. 8A was obtained. Since there is a step difference of about 5 μm between the upper cylinder 31 and the lower cylinder 32 and the behavior of the tape-shaped recording medium 39 becomes unstable, the overall flying height of the tape-shaped magnetic recording medium 39 from the cylinder circumferential surface is reduced. It gets bigger and the tape touch gets worse.

As a cylinder device of a recording / reproducing device that solves the above problems, there is one disclosed in Japanese Utility Model Publication No. 59-89449. 7 and 11 show an example of a cylinder device of a recording / reproducing device similar to the device described in Japanese Utility Model Laid-Open No. 59-89449. In FIGS. 7 and 11, in order to suppress the floating amount of the tape and improve the tape touch, a taper portion 23 is provided on the lower end of the upper cylinder 21 of the cylinder device over the entire circumference, and the diameter of the lower cylinder 22 is increased. The diameter is smaller than that of the cylinder 21. The tape-shaped magnetic recording medium 29 is wound around such a cylinder device, and the flying height from the cylinder peripheral surface of the tape-shaped recording medium 29 that is in sliding contact with the peripheral surface of the cylinder device is measured. As shown in FIG. Good results were obtained.

From FIG. 8B, it can be seen that the provision of the taper portion 23 reduces the flying height of the tape-shaped magnetic recording medium 29 as a whole and stabilizes the tape behavior. When the flying height of the tape-shaped magnetic recording medium 29 is reduced, the head touch of the tape-shaped magnetic recording medium 29 is improved, and since the upper cylinder edge portion that promotes wear is not present, the tape-shaped magnetic recording medium 29 is abnormal. As compared with the examples shown in FIG. 5 and FIG. 6, the characteristics are improved, such as reduction in wear.

[0050]

[Problems to be solved by the device]

 However, according to the cylinder device of the magnetic recording / reproducing apparatus described in Japanese Utility Model Laid-Open No. 59-89449, since the flying height of the tape-shaped magnetic recording medium 29 is reduced, the tape-shaped magnetic recording medium 29 is described below. Subtle displacement occurs in.

As shown in FIG. 9, when the upper cylinder 21 rotates counterclockwise, the point where the peripheral surface of the upper cylinder 21 starts to come into contact with the tape-shaped recording medium 29 is the inlet portion 26 and the peripheral surface of the upper cylinder 21. The point where the magnetic recording medium starts to separate from the medium 29 is defined as the outlet portion 28, and the central portion thereof is defined as the central portion 27, and the displacement amount from the cylinder surface of the tape-shaped magnetic recording medium was measured at these three points. The result is shown in FIG. In addition, (a) shows the measurement result at the inlet portion 26, (b) shows the central portion 27, and (c) shows the measurement result at the outlet portion 28. From this result, the amount of displacement suddenly drops immediately after the inlet 26, especially immediately after the magnetic head (A in FIG. 10A), and the subsequent amount of displacement increases due to the recoil of this drop, and overall However, the amount of displacement tends to increase. When the displacement amount increases, the uneven wear 35 caused by the tape-shaped magnetic recording medium rubbing the cylinder device increases as shown in FIG.

The present invention has been made to solve the above problems, and provides a cylinder device of a magnetic recording / reproducing apparatus that suppresses uneven wear caused by a slight displacement of a tape-shaped magnetic recording medium. With the goal.

[0070]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention comprises a rotating upper cylinder and a fixed lower cylinder, and the diameter of the upper cylinder is made larger than that of the lower cylinder. A taper is provided over the entire circumference, a head window is provided in a part of the lower end of the cylinder, a magnetic head is provided in the head window, and a tape-shaped magnetic recording medium is wound around a part of the outer peripheral surface of the cylinder. In a cylinder device of a magnetic recording / reproducing device configured to form a recording signal track in an oblique direction of this recording medium, at least the rear end of the upper head cylinder of the magnetic head in the direction of rotation during reproduction and the opposing end The distance from the edge of the head window is 0.3 mm or less, and at least the rear corner of the head window with respect to the rotation direction of the upper cylinder during reproduction. There it characterized in that provided having the above radius 0.2 mm.

[0080]

[Action]

 By setting the distance between the rear end of the upper cylinder of the magnetic head in the direction of rotation and the edge of the head window facing it to 0.3 mm or less, the tape-shaped recording medium drops suddenly immediately after the magnetic head. Disappears. Further, by making the rear corner of the head window with respect to the rotation direction of the cylinder a radius of 0.2 mm or more, it is possible to weaken the contact between the tape-shaped magnetic recording medium and the upper cylinder after passing through the magnetic head. Wear can be avoided.

[0090]

【Example】

 An embodiment of a cylinder device of a magnetic recording / reproducing apparatus according to the present invention will be described below with reference to the drawings. 1 to 3, a cylinder device used in a magnetic recording / reproducing device such as a DAT is composed of a cylindrical lower cylinder 2 and an upper cylinder 1 rotatably attached to the upper side of the lower cylinder 2. The lower portion of the upper cylinder 1 is chamfered over the entire circumference to form a tapered portion 3. A plurality of head windows 10 are formed in the tapered portion 3 at regular intervals in the circumferential direction. The head window 10 is formed by notching the tapered portion 3, and the corners 5 and 5'above the head window 10 have a radius R of 0. It is formed to have an arc of 2 mm or more. Further, the magnetic head 4 is mounted in the head window 10 via the head pedestal 8, and the rear end 4b of the magnetic head 4 with respect to the rotational direction during reproduction of the cylinder 1 and the edge of the head window 10 facing the rear end 4b. The distance W 1 is set to 0.3 mm or less.

In the cylinder device as described above, the tape-shaped magnetic recording medium 9 obliquely abuts from the upper cylinder 1 to the lower cylinder 2, and travels in the same direction as the rotating direction of the upper cylinder 1 during reproduction by a medium conveying mechanism (not shown). To do. Since the distance W between the edge of the magnetic head 4 and the head window 10 is set to 0.3 mm or less, the tape-shaped magnetic recording medium 9 does not fall between the magnetic head 4 and the head window 10, and The amount of displacement during traveling can be reduced. Further, the tape-shaped magnetic recording medium 9 can be brought into smooth contact with the magnetic head 4 by forming the corners 5 and 5'of the head window 10 into arcs having a half diameter of 0.2 mm or more. The displacement of the cylinder device of the magnetic recording device as described above was measured at the inlet portion, the central portion and the outlet portion of the head window 10 in the same manner as in the conventional measuring method shown in FIG. was gotten. As is clear from FIG. 4, it can be seen that the sudden drop at the entrance of the recording medium 9 with respect to the cylinder disappears, and the displacement amount of the medium 9 overall decreases. When the amount of displacement is reduced, the contact of the medium with respect to the cylinder is weakened, the wear of the cylinder is reduced, and the life of the apparatus and the tape-shaped magnetic recording medium 9 can be remarkably extended.

In FIG. 3, the distance between the front end 4a of the magnetic head 4 in the direction of rotation of the upper cylinder 1 and the edge of the head window 10 facing the front end 4a is also preferably 0.3 mm or less. In the present invention, at least the distance between the rear end 4b of the magnetic head 4 in the direction of rotation of the upper cylinder 1 and the edge of the head window 10 facing the rear end 4b should be 0.3 mm or less. Similarly, it is desirable that the front corner portion 5 ′ of the head window 10 with respect to the rotation direction of the upper cylinder 1 is an arc having a radius of 0.2 mm or more. It suffices that the corner portion 5 on the side be an arc having a radius of 0.2 mm or more.

[0120]

[Effect of the device]

 According to the present invention, at least the distance between the rear end of the magnetic head in the direction of rotation of the upper cylinder and the edge of the head window facing it is set to 0.3 mm or less, and at least the rear side of the head window in the direction of rotation of the cylinder. Since the corners of the tape have an arc with a radius of 0.2 mm or more, it is possible to reduce the displacement of the tape-shaped recording medium and weaken the contact of the recording medium with the edge of the head window. It is possible to reduce uneven wear of the device and reduce damage to the recording medium.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a cylinder device of a magnetic recording device according to the present invention.

FIG. 2 is an enlarged side sectional view of the same.

FIG. 3 is an enlarged front view of the main part of the same.

FIG. 4 is a graph showing displacement amount measurement values of the tape-shaped recording medium in the above embodiment.

FIG. 5 is a perspective view showing an example of a cylinder device of a conventional magnetic recording device.

FIG. 6 is an enlarged side sectional view of the same.

FIG. 7 is a side sectional view showing another example of a cylinder device of a conventional magnetic recording device.

FIG. 8 is a graph showing, in comparison, measured values of the flying height of a recording medium in a cylinder device of each conventional magnetic recording device.

FIG. 9 is a plan sectional view showing a position where a displacement amount of a recording medium with respect to a cylinder is measured.

FIG. 10 is a graph showing a measured displacement amount of a recording medium in a cylinder device of a conventional magnetic recording device.

FIG. 11 is a perspective view showing an example of a cylinder device of a conventional magnetic recording device.

[Explanation of symbols]

 1 upper cylinder 2 lower cylinder 3 taper portion 4 magnetic head 9 tape-shaped magnetic recording medium 10 head window

Claims (1)

[Scope of utility model registration request] 1. A rotating upper cylinder and a fixed lower cylinder are provided, wherein the diameter of the upper cylinder is larger than the diameter of the lower cylinder, and a taper portion is provided at the lower end of the upper cylinder over the entire circumference. A head window is provided in a part of the lower end of the cylinder, a magnetic head is provided in the head window, a tape-shaped magnetic recording medium is wound around a part of the outer peripheral surface of the cylinder, and recording is performed in an oblique direction of this recording medium. In a cylinder device of a magnetic recording / reproducing apparatus configured to form a signal track, at least a distance between a rear end of the magnetic head with respect to a rotational direction during reproduction of the upper cylinder and an edge portion of the head window facing the rear end is determined. It should be 0.3 mm or less, and at least the rear corner of the head window with respect to the rotation direction during reproduction of the upper cylinder should have a radius of 0.2 mm or more. The cylinder device of the magnetic recording / reproducing device provided in the.