JPS628348A - Reel motor control device - Google Patents

Abstract

PURPOSE:To wind stably a tape at a constant tape speed by switching a tension control loop into the number of revolution control loop the moment the tape end detaches a reel and applying control so that the number of revolution error signal is made coincident in advance with a tension error signal before the changeover. CONSTITUTION:A memory output 30 is inputted to the number of revolution error signal generator 25, where the the center value of the number of revolution is controlled so that the potential of the tension error signal 16 is made coincident with that of the number of revolution error signal 26. No tension detection output 24 is outputted until the moment the tape end detaches a winding reel 31, a switch 17 selects the tension error signal to constitute the tension loop. When the tape end detaches the winding reel 31, a tape tension post 49 is moved immediately toward the arrow, a tension output 24 is outputted and the switch circuit 17 is switched to select the number of revolution error signal. The tape is wound while the tape speed is controlled constantly in the speed control loop.

Description

TECHNICAL FIELD The present invention relates to a reel motor control device, and more particularly to a reel motor control device in a magnetic recording/reproducing device such as a video tape recorder.

BACKGROUND ART Conventionally, in a tape winding control system for this type of apparatus, either tape tension control or speed control such as keeping a tape timer signal at a constant frequency has been adopted for the reel motor.

In conventional take-up control, in any of the above methods, the tape is wound up and a normal control state cannot be maintained from the moment it leaves one take-up reel. In other words, when winding with tension control,
Since the tension sensor post placed on the tape running system moves in the direction of zero tension, the tension is controlled in the stronger direction, resulting in the tape speed increasing once and then stopping.

On the other hand, even when winding is performed using speed control with a tape timer signal at a constant frequency, when the tape leaves one take-up reel, the tension applied to the rotating roller for generating the tape timer signal decreases, causing slippage. Therefore, its frequency decreases.

As a result, the tape speed is temporarily increased and then stopped.

In either case, the tape cannot be wound smoothly, resulting in uneven winding speed, which causes serious damage such as uneven tape winding and damage to the rotating head.

Purpose of the Invention The present invention has been made to eliminate the drawbacks of the above-mentioned conventional products.The purpose of the present invention is to be able to wind a tape stably at a constant tape speed, thereby reducing stress on the tape winding. It is an object of the present invention to provide a reel motor control device that can prevent damage to the tape itself, other magnetic heads, etc. without adding any damage to the tape itself or other magnetic heads.

Composition of the Invention A reel motor control device according to the present invention includes a tension control means for controlling tape tension, a rotation speed control means for controlling the rotation speed of a reel motor, a tape end detection means for detecting a tape end, and a tape end detection means for detecting a tape end. tape separation detection means for detecting that the tape has been separated from the tape reel; and a control signal for the rotation speed control means is applied to the control signal for the tension control means in response to generation of a tape end detection signal by the tape end detection means. and control loop switching means for controlling the reel motor by switching from the tension control means to the rotation speed control means in synchronization with the timing at which the tape separation detection signal is generated by the tape separation detection means. It is characterized by

Example Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a reel motor control system diagram according to an embodiment of the present invention, and FIG. 2 is a plan layout diagram of a tape running system of a video tape recorder to which the embodiment of the present invention is applied. To wind the tape, the take-up reel 31 and the supply reel 51 each rotate in the direction of the arrow when the apparatus is operating in the rewind mode. Timer signal 1 is used as tape speed information. This is taken out from the detection section at the bottom of the timer roller mechanism 48 in FIG.

Timer signal 1 is input to tape speed controller 2 where speed control error signal 3 is generated to control the rotational speed of the take-up reel motor of take-up reel assembly 6 via take-up reel motor drive amplifier 4.

This control loop constitutes a tape speed control loop that uniquely determines the tape feed speed.

The take-up reel tack signal 7 is rotation speed information taken out from a detector at the bottom of the take-up reel motor. The supply reel tack signal 9 is the rotation speed information of the supply reel motor taken from a detector at the bottom of the supply reel motor in the supply reel assembly 21 . Tape end detector 1
A timer signal 1, a take-up reel tack signal @7, and a supply reel tack signal 9 are input to 0. Here, when the pulse number ratio of the take-up reel tack signal 7 to the timer signal 1 exceeds a predetermined ratio, a reverse tape end signal 11 indicates that the tape is in the tape end region when traveling in the rewinding direction. is output. Similarly, when the pulse number ratio of the supplied reel tack signal 9 to the timer signal 1 exceeds a predetermined ratio, a forward tape end signal 8 is output indicating that the tape is at the end of the tape when traveling in the fast forward direction. be done.

When these tape end signals are input to the tape speed controller 2, if the tape speed is equal to or higher than a predetermined speed, the tape speed is controlled to be decelerated to the predetermined tape speed. By determining the tape speed before the tape leaves the reel, the attitude of the tape is stabilized and the outer periphery of the rotating drum 44 is stabilized until the tape 32 leaves the take-up reel 31 and is completely wound onto the supply reel 51. This is to protect the video head attached to the tape by weakening the impact caused by the tape edge.

The tension sensor signal 14 is tape tension information taken out from the lower detection section of the tension post mechanism 49 shown in FIG. This is tension controller 15
The tension error signal 16 is inputted to and compared with a tension reference signal to generate a tension error signal 16. This signal is transmitted to the switch circuit 17. It operates to control the torque of the reel motor of the supply reel mechanism 21 via the drive amplifier 19 to obtain a constant tape tension. This control loop constitutes a so-called tape tension control loop. As mentioned above, the tape running in the fast forward and rewind modes is controlled by using tape speed control in the control loop of the take-up reel motor and tape tension control in the control system of the supply reel motor. .

Now, looking at the operation when winding the tape onto the supply reel in the rewind mode, each reel is rotating in the direction of the arrow in FIG. When the amount of tape remaining on the take-up reel 31 decreases and reaches the tape end area, the tape speed is controlled to be decelerated to a speed determined by the movement of the tape speed control system. As the tape advances further and leaves the take-up reel 31, it is no longer supported and the tape tension weakens. the result,
The tape tension post 49 in FIG. 2 moves in the direction of the arrow in the figure. Here, the tape tension post 49 works to move in the direction of the arrow when the tape tension becomes weaker and in the opposite direction when it becomes stronger. In this state, the tape tension control system applies torque to the supply reel motor in order to maintain the tape tension value constant, and as a result, the tape speed is accelerated. This will continue until the end of the tape passes the tape sensor 46.

The tape sensor 46 detects the presence or absence of a tape, and when it is detected that there is no tape, all movable modes are canceled. That is, the rotating drum 44. The capstan 36, the supply reel motor, and the take-up reel motor all enter brake control and are stopped. Therefore, the supply reel on which the tape is finally wound will experience uneven speed from acceleration to deceleration in a short period of time. This speed change is increased because one side of the tape is free compared to when operating with tape wound on both reels. This causes uneven winding of the tape and causes damage to the tape. In extreme cases, damage may be caused not only to the outer periphery of the reel but also to the inner part of the reel. Furthermore, when the end of the tape is accelerated around the rotating drum 44 and passes through it, it may give an impact to the video head disposed on the outer periphery of the tape, giving it a shock of 1 (12). The operation is intended to be achieved by adding a simple electronic circuit, and the operation will be explained below.

When the tape runs in the rewind mode and reaches the tape end area, the tape speed control system decelerates the tape speed to a predetermined speed as described above. The delay device 12 delays the timing at which the speed tape end signal 11 is output, and outputs the delayed output 13 at a timing obtained by adding a margin to the transition time of deceleration control.

On the other hand, the take-up reel tack signal 9 is input to the take-up reel motor rotational speed error signal generator 25. Here, a rotational speed error signal 26 is generated according to an increase or decrease in the rotational speed with respect to the specified rotational speed. This signal is transmitted to the switch circuit 17. The rotation speed of the reel motor in the supply reel assembly 21 is controlled to be constant through the drive amplifier 19. This control loop constitutes a rotation speed control loop.

The tension error signal 16 and the rotational speed error signal 26 are selected by a switch circuit 17 to form a tension control loop or a rotational speed control loop, respectively. The switch circuit 17 is controlled by a tension detection output 24 which is output when the tape tension is detected to be below a certain value.

The tension detector 23 detects that the tension is less than a certain value by comparing the tension sensor signal 14 and the reference voltage 22, and generates a tension detection output 24. A reverse tape end signal 11 is input here to prohibit the tension detection output 24 from being output in other areas.

This prevents the tension control loop from accidentally switching to the rotational speed control loop when it should be operating.

The tension detection output 24 is not output until the tape reaches the reverse tape end area, the aforementioned deceleration control is completed, the tape advances further, and the end of the tape leaves the take-up reel 31, and the switch 17 outputs a tension error signal. is selected to configure the tension loop. Immediately after the end of the tape leaves the take-up reel 31, the tape tension post 49 moves in the direction of the arrow, the tension detection output 24 is output, and the switch circuit 17 switches to a rotational speed error signal. Thereafter, the tape can be wound while the tape speed is controlled at a constant level using the rotational speed control loop.

Here, it is necessary to suppress the change in tape speed before and after the tape end leaves the take-up reel 31 so as not to apply stress to the tape.

Next, I will explain its operation. When the tension loop is configured and operating, the tension error signal 1
6 and the rotation speed error signal 26 are input to a differential amplifier 27, which amplifies the difference voltage between the two error signals and outputs a rotation speed center value control signal 28. The memory circuit 29 outputs an output 30 with the input signal having a gain of 1 before the output of the delayed output 13. When the delayed output 13 is output, the potential of the input signal at that time is memorized, and thereafter the memorized constant potential is output. This memory output 30 is input to the rotation speed error signal generator 25 to control the center value of rotation speed, and operates to make the potential of the rotation speed error signal 26 coincide with the tension error signal 16. Here, the delay output 13 is generated at a timing sufficient for the tape speed control loop to complete deceleration control in the tape end area and for the potential of the rotational speed error signal 26 to match the tension error signal 16 in this running state. It is set to be output.

With this configuration, it is possible to make the error signal voltage when the take-up reel motor is controlled by the tension control loop and the error signal voltage when switching to the rotation speed control loop to be the same in advance. When switching from the tension control loop to the rotational speed control loop, it becomes possible to wind the tape while maintaining a constant tape speed without changing the rotational speed of the take-up reel motor.

By setting the tape speed in the tape end area to a value that provides the best winding conditions, including the arrangement of the tape running system of the device, it is possible to wind the tape while keeping that value constant. .

In addition, in Fig. 2, 33 is a guide roller, 34.37
, 42, 43, and 45 are guide posts, 38, 39 is an audio head, 40, 47 is an erasing head, and 41 is an impedance roller, respectively.

11 11 As explained above, the present invention switches from the tension control loop to the rotation speed control loop at the moment the end of the tape leaves the reel, and also sets the rotation speed error signal to the tension error signal in advance before switching. By controlling the speed so that the tape remains constant, the tape can be wound stably at a constant tape speed with almost no change to the tape speed before switching. This has the effect of not only preventing damage, but also preventing unnecessary impact from being applied to the video head.

Further, the present invention can be constructed using only a simple electronic circuit without adding any special detection mechanism in addition to the mechanism conventionally provided in the tape running system. Furthermore, as is clear from the above explanation, it is possible to always wind the tape at a constant speed regardless of the diameter of the supply reel or the amount of tape wound on it, which makes it very difficult to operate. There is an effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a plan layout diagram of a tape running system of a video cheap reader applied to the embodiment of FIG. 1. Explanation of symbols of main parts 10...Tape end detector 12...Delay circuit 15...Tension controller 17...
... Switch circuit 21 ... Supply reel motor 23 ... Tension detector 25 ... Speed controller 29 ...
・Memory 31...Take-up reel 32...Tape 46...Tape sensor 49...Tension post 51...Supply reel

Claims (1)

[Claims] A tension control means for controlling tape tension, a rotation speed control means for controlling the rotation speed of the reel motor, a tape end detection means for detecting the tape end, and a tape separation detection means for detecting that the tape has been separated from the tape reel. means for controlling the control signal of the rotation speed control means to be substantially equal to the control signal of the tension control means in response to generation of a tape end detection signal by the tape end detection means; A reel motor control device comprising: control loop switching means for controlling the reel motor by switching from the tension control means to the rotation speed control means in synchronization with the generation timing of a separation detection signal.