JPH04229443A - Tape driving device - Google Patents

Abstract

PURPOSE:To restrain the change of tape tension and to make a time required for switching a speed short by executing correction according to the detecting output of torque which is changed in proportion to the winding diameters of a supply and a take-up reel and generated by the driving torque control system of a reel motor CONSTITUTION:The output (a) of a rotational speed detector 4 is inputted to a speed detection circuit 17 and the speed change (acceleration) of a term that a capstan motor 3 is accelerated and decelerated is detected. Besides, the output (b) thereof is inputted to an S reel driving torque correction circuit 18 and a T reel driving torque correction circuit 19. According to the speed change, the set data (c) of S motor driving torque impressed on an S motor driving circuit 9 and the set value of T motor driving torque impressed on a T motor driving circuit 14 are corrected as much as a prescribed value.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape drive device for a magnetic recording/reproducing device, and in particular, a rotary head sequentially records information signals as a recording locus inclined with respect to the longitudinal direction of a magnetic tape. The present invention provides a tape drive device that is effective for use in a rotary head type magnetic recording/reproducing device that performs special playback by changing the tape speed during playback by a predetermined value with respect to the tape speed.

0002

2. Description of the Related Art Conventionally, in a rotary head type magnetic recording/reproducing device, a supply/winding device is used as a means for controlling the driving torque of a motor that drives a reel that supplies and winds a magnetic tape driven through a capstan shaft. By detecting the tape winding diameter of each reel to be picked up and applying a drive current proportional to the tape winding diameter to each motor, a driving torque proportional to the winding diameter is generated and the tape tension is kept almost constant. There is a control method. The outline is shown in Figure 2.

In FIG. 2, a tape 1 driven by a capstan shaft 2 is supplied from a supply reel (hereinafter referred to as S reel) 7 driven by a supply reel motor (hereinafter referred to as S motor) 8, and is wound. It is wound onto a take-up reel (hereinafter referred to as T-reel) 12 driven by a take-up reel motor (hereinafter referred to as T-motor) 13 . The rotational speed of the capstan motor 3 directly connected to the capstan shaft 2 is detected by a speed detector 4, and the output a of the speed detector 4 is input to a speed control circuit 5, so that the rotational speed is controlled. It is controlled to a predetermined value set by the speed setting circuit 6. The S motor 8 operates to generate a driving torque in the direction in which the S reel 7 winds up the tape in order to apply a predetermined tape tension to the magnetic tape by the S motor drive circuit 9. S
By inputting the output of the S motor drive torque setting circuit 10 to the motor drive circuit 9, it is controlled to a predetermined value proportional to the tape winding diameter of the S reel detected by the S reel winding diameter detector 11. . The T motor 13 is operated by a T motor drive circuit 14 to generate a drive torque in the tape winding direction, and the drive torque is input to the T motor drive circuit 14 by the output of the T motor drive torque setting circuit 15. As a result, it is controlled to a predetermined value proportional to the tape winding diameter of the T-reel detected by the T-reel winding diameter detector 16.

0004

[Problems to be Solved by the Invention] In such conventional devices, when changing the speed of the capstan motor,
When the capstan motor starts accelerating at an acceleration α, as is well known, the tape tension Ts at the exit of the S reel increases and the tape tension Tt at the entrance of the T reel decreases. Therefore, if the acceleration α of the capstan motor is made larger than a predetermined value in order to quickly increase the speed of the tape to a predetermined speed, the tape tension will become larger than the predetermined value at the exit of the S reel, and the tape slack will be reduced at the entrance of the T reel. This may occur and may interfere with tape speed switching operations.

[0005]

[Means for Solving the Problems] In order to solve the above problems, the tape drive device of the present invention is provided with means for detecting changes in the rotational speed of the capstan motor, and the tape drive device of the present invention is provided with means for detecting changes in the rotational speed of the capstan motor, and the winding diameters of the supply and take-up reels are adjusted. The torque generated by the drive torque control system of the supply and take-up reel motors, which vary in proportion to each other, is corrected by a predetermined value in accordance with the detection output of the detection means.

[0006]

[Operation] With the above configuration, when the capstan motor accelerates, the present invention reduces the generated torque of the S motor, which is proportional to the winding diameter of the S reel, by a predetermined value, and reduces the torque generated by the S motor, which is proportional to the winding diameter of the T reel, by a predetermined value. By increasing the torque generated by the T motor by a predetermined value, it is possible to suppress an increase in tape tension at the S reel outlet and tape slack at the T reel inlet. Also, when the capstan motor decelerates, the torque generated by the S motor is increased by a predetermined value, and the torque generated by the T motor is decreased by a predetermined value, thereby reducing tape slack at the S reel outlet and reducing tape slack at the T reel inlet. It is possible to suppress an increase in tape tension.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing an embodiment of a tape drive according to the present invention, and the same parts as those in the conventional structure shown in FIG. 2 are designated by the same reference numerals. The difference is that a speed change detection circuit 17 that detects changes in the rotational speed of the capstan motor 3 is added, and the period in which the capstan motor 3 is accelerated or decelerated by inputting the output a of the rotational speed detector 4. detects the speed change (acceleration), and inputs its output b to the S reel drive torque correction circuit 18 and the T reel drive torque correction circuit 19, respectively, and is applied to the S motor drive circuit 9 according to the speed change. The S motor drive torque setting data c and the T motor drive torque setting data d applied to the T motor drive circuit 14 are each corrected by predetermined values. That is, when accelerating or decelerating the capstan motor 3, the change in tape tension at the S reel outlet and T reel inlet is within a predetermined value.
The values of the torque generated by the S motor 8 and the torque generated by the T motor 13 are each corrected by predetermined values.

In the above embodiment, the change in rotational speed (acceleration) of the capstan is detected by the speed change detection circuit 17 from the output of the speed detector 4, and the S motor 8 and the T motor However, if the speed of the capstan motor 3 is switched stepwise to a plurality of predetermined speeds, when the speed is switched, the drive torque of the capstan motor 3 is changed at the predetermined speed. Since the time required to achieve this and changes in acceleration can be experimentally confirmed in advance, when switching speeds, the correction circuit uses predetermined setting data corresponding to the changes in acceleration for a preset period corresponding to this time. 18 and 19
It is also possible to apply it to

[0009]

As described above, according to the configuration of the present invention, changes in tape tension at the S reel exit and T reel entrance caused by acceleration/deceleration of the capstan motor can be prevented in advance regardless of the value of the acceleration α of the capstan motor. This is extremely useful in practice since it can be kept within a predetermined value and the time required to change the speed of the capstan motor can be minimized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the main parts of a tape drive device in an embodiment of the present invention.

[Fig. 2] Block diagram showing the main parts of a conventional tape drive device

[Explanation of symbols]

1 Tape 2 Capstan shaft 3 Capstan motor 4 Capstan motor speed detector 5 Capstan motor speed control circuit 6 Capstan motor speed setting circuit 7 S reel 8 S motor 9 S motor drive circuit 10 S motor drive torque setting circuit 11 S reel winding diameter detector 12 T reel 13 T motor 14 T motor drive circuit 15 T motor drive torque setting circuit 16 T reel winding diameter detector 17 Capstan motor speed change detection circuit 18
S motor drive torque correction circuit 19 T motor drive torque correction circuit

Claims (2)

[Claims] 1. A drive torque of a motor that drives the supply reel and the take-up reel is changed in accordance with the acceleration of a capstan that drives the magnetic tape from the supply reel toward the take-up reel. Tape drive. 2. When switching the rotational speed of a capstan that drives the magnetic tape from the supply reel toward the take-up reel, the supply reel and the take-up reel are each driven by a predetermined value for a predetermined period of time. A tape drive device characterized in that the drive torque of a motor is changed.