JPS58164044A - Tape tension controlling device of magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent damage of a tape and failure of a reproduced picture quality, by providing a tension detecting lever, and optionally deciding the tape running tension of the circumferential part of each cylinder in case of FWD and REV. CONSTITUTION:Magnitude of tension operating on a tape 20 is expressed as magnitude of displacement of a tension post 23 which is made to press-contact with the tape 20, and a tension detecting lever 3, its displacement quantity becomes a quantity of electricity by a photointerrupter 4, this quantity of electricity is compared with a reference signal of a reference signal generator 40 by a comparing circuit 41, and this compared output is sent to a reel motor driving circuit 43 through an integration circuit 42. By an output of the reel motor driving circuit 43, rotation of the reel motor is controlled, and its adjustment is executed so that tension of the tape 20 becomes constant.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tension control device for a magnetic recording/reproducing device, and its purpose is to stably run a magnetic tape with a constant tape tension regardless of the winding diameter of the magnetic tape. 2) In conventional magnetic recording and reproducing devices, the tension detection lever was used only when traveling in the direction in which the supply side was the load (hereinafter referred to as FWD). Therefore, when traveling in the direction in which the supply side is the drive (hereinafter referred to as REV), the intended running tension cannot be obtained and the running tension becomes unstable, such as abnormal tension around the rotating head cylinder of a VTR. This has disadvantages in that the tape may be damaged due to this or an appropriate contact pressure to the head cannot be obtained, resulting in poor reproduced image quality.

The present invention eliminates these drawbacks and provides a tape tension control device for a magnetic recording/reproducing device that can obtain stable tape running tension.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. Fig. 1 is a schematic configuration diagram of a VH8 type video tape recorder (VTR) which is an embodiment of the present invention;
FIG. 4 is an explanatory diagram of the operation of the main parts of the device.

In the figure, 20 is a magnetic tape that is pulled out from a VH3 type cassette 21, 22 is a supply side reel stand, 35 is a take-up side reel stand, 23 is a tension post rotatably supported on the chassis, and 24 is a Fixed shaft installed in the chassis (
25 is a full-width erase head, 26. 29 is a height regulating post for pulling out the magnetic tape 2o from the cassette 21, and 27 is rotatably supported by a P1 post (not shown).
．． Reference numeral 28 denotes an inclined post installed opposite the height regulating boss 26 and 29.

30 is an impedance roller rotatably supported by a shard, 31 is an audio erase head, 32 (d,
t-74 ion control head, 33 is a magnetoresistive head (MR head), 34 is a P4 post, 36 is a cylinder equipped with a rotary head (not shown), 14 is a cap for stopping the magnetic tape 2o while it is running. This is a pinch roller that can be freely pressed against and separated from the stun 15. 1 is a tension arm having the tension post 23 implanted therein, and is rotatably supported by a fixed shaft 2 implanted in the chassis. A tension detection lever 3 is installed at the other end of the tension arm 1, and a photointerrupter 4 is installed at the tip of the tension detection lever 3 on the chassis. A tension arm spring 5 is installed at the other end of the tension arm with the chassis as the fixed end, and the tension arm 1 is always biased in the direction of the arrow with the fixed shaft 2 as a pivot point. There is.

Next, the operation of this device will be explained.

In FIG. 1, the FWD running direction where the supply side reel stand 36 is the load is indicated by arrow F, and the direction of RE where the supply side reel stand 35 is the drive.
In the running direction V, the tape runs in the direction of arrow H. As shown in FIG. 2, the FWD running tension T. and T1 vector resultant FxL - tension P of tension arm spring 5
xl is a reel control method in which the balance is balanced, and in this balanced state, the tension detection lever 3. At the slit section 7, the amount of light from the photointerrupter 4 becomes 1/2 of the total.
) Note that this tape tension control is performed using the tension post 20. as shown in FIG. Tension detection lever 3, photointerrupter 4, reference signal generator 40. Comparison circuit 41, integration circuit 42 and motor drive circuit 4
This is done using a closed loop consisting of 3. That is, tape 2
The magnitude of the tension acting on the tape 2o is expressed as the magnitude of the displacement of the tension post 23 in contact with the tape 2o and the tension detection lever 3, and the amount of displacement is converted into an electrical quantity by the photointerrupter 4, and this electrical quantity is converted into an electrical quantity by the comparison circuit 41. The reference signal of the reference signal generator 4o is compared with the reference signal, and the comparison output is sent to the reel motor drive circuit 43 via the integration circuit 42, and the output of the reel motor drive circuit 43 causes the rotation of the reel motor (not shown). The control is performed so that the tension of the tape 2o remains constant.

When a reversal command is issued from the FWD direction to the REV direction, by increasing the torque of the supply side reel motor (not shown), the reel is moved to the Slin' wall 8 so as to be located at the center of the optical axis. R
During EV, the tension arm 1 rotates in the direction of arrow B around the fixed shaft 2, so %)
((Spring constant of tension arm spring 6 blade nipper 5×deflection amount)+(P))Xi.

At the same time, θ2>θ3, and the wrapping angle around the tension post 23 changes.

By arbitrarily changing the distance t between each slit wall from the relationship of T1(R)=TO@)×eμ"3 (μ, - friction coefficient), the FWD running tension and the REV running tension can be adjusted arbitrarily. It is possible to determine
Regardless of the V mode, a constant and stable running tension could be obtained.

In this way, according to this embodiment, the tension detection lever is provided with one photointerrupter and a slit portion
FWD is achieved by selectively using both sides of the slit portion during WD and REV driving, and arbitrarily determining the interval between the slit portions.

It is now possible to arbitrarily determine the tape running tension around each cylinder during REV, and it is also possible to eliminate tension deviations due to differences in winding diameter.
Furthermore, problems such as damage to the tape due to abnormal tension around the cylinder and poor quality of reproduced images due to inability to obtain appropriate contact pressure to the video head have been solved.

As described above, according to the present invention, stable tape tension can be obtained with a simple configuration regardless of the tape winding diameter, and, for example, a high-quality VTR can be easily realized.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a magnetic recording/reproducing device which is an embodiment of the present invention, FIG.
FIG. 3B is a partial sectional view of the same, FIG. 3A is an explanatory diagram of the operation of the main part of the same device, FIG. 3B is a partial sectional view of the same, and FIG. 4 is a block diagram of the tension control section of the same device. 1.1...Tension arm, 2■-...Fixed shaft, 3...Tension detection lever, 4...
・Photo interrupter, 5...l5II tension arm spring, 6...cassette post, 7...
... Slit slit wall for FWD ... Slit slit wall for REV 4 ... Pinch roller, 15@.
Φ・0 capstan shaft, 20...magnetic tape,
21...VHS system cassette, 22------
-Supply side reel stand, 23mmammm tension post, 24...1l-P1 post, 26...
Full width erase head, 26... Entrance side height regulation post, 27... Entrance side inclined post, 28...
・・Exit side inclined post, 29・・・Exit side height regulation post, 3o・・・Fist/impedance roller, 31・
...0. Audio erase Henodo, 32... too...
・Audio control head, 33...M
R head, 34...P4 post, 36...
...Take-up side reel stand, 36...Cylinder, 40
...Reference signal generator, 41 ... Comparison circuit, 42 ... Integration circuit, 43 ... Reel motor drive circuit. Name of agent: Patent attorney Toshio Nakao and one other person ＼ Figure 1

Claims (1)

[Claims] A take-up reel stand for winding a magnetic tape, a reel motor for rotating the take-up reel stand, a supply reel stand for supplying the magnetic tape, a control unit for controlling rotation of the supply reel stand, and the reel motor. a tension control unit that controls the rotational speed of the magnetic tape; a tension arm that is biased such that one end comes into contact with the magnetic tape and is rotatably supported with respect to a base; and detects displacement of the tension arm; The tension control section is operated according to the amount of displacement.