JPH09212955A - Device and method for control of tape speed of magnetic recording and reproducing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a device by which the feed load of a feed-side reel is reduced in a fast forwarding/rewinding operation and by which a smooth and high-speed running operation can be achieved by a method wherein a reeling- diameter computing part which detects a reeling-diameter ratio on the basis of an FG pulse is installed and a feeding-force control part is installed. SOLUTION: FG pulses from a T-side reel motor 3 and an S-side reel motor 3 are input respectively to cycle detection circuits 42, 42, and the cycle detection circuits 42, 42 detect rotation cycles of the respective reel motors 3, 3 on the basis of the FG pulses. Outputs from the cycle detection circuits 42, 42 are input to a reeling-diameter computing part 41. A mode processing part 5 is provided with a control-signal transmission part 52 to which a signal from a mode discrimination circuit 40 is input and with a reeling-force control part 50 which outputs a voltage value to be supplied to the reeling-side reel motor 3. In addition, the mode processing part 5 is provided with a feeding-force control part 51 which outputs a voltage value to be supplied to the reeling-side reel motor 3 and with a direction-of-rotation control part 53 which supports the reel motor 3 to its direction of rotation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling a tape speed when fast-forwarding and rewinding a magnetic tape in a magnetic recording / reproducing device such as a VTR, and a tape speed control method.

[0002]

2. Description of the Related Art FIG. 5 is a plan view of such a magnetic recording / reproducing apparatus. On the chassis (7), a pair of reel stands (1) that fits on the reels in the cassette (60) and winds the magnetic tape (6)
A rotary cylinder (70) for recording / reproducing through (2) and the magnetic tape (6) is provided, and the reel stand (2) and the rotary cylinder are provided.
Between pinch roller (70), pinch roller (72) and capstan motor
(71) is provided. The pinch roller (72) and the capstan motor (71) sandwich and convey the magnetic tape (6). As is well known, an idler mechanism (73) is provided between the reel stands (1) and (2).
Is provided, and the power from the capstan motor (71) is transmitted to one of the reel stands (1) and (2) via a gear train (not shown) and an idler mechanism (73).

In recent years, such a device is required to fast-forward, fast-forward and rewind (hereinafter referred to as FF / REW) the magnetic tape (6). Therefore, the reel stand (1) (2) is FFed.
What is driven by a large torque corresponding to / REW is required. In the above recording / reproducing apparatus, since the capstan motor (71) conveys the magnetic tape (6),
Originally, it does not require a large driving torque. Therefore, the drive torque corresponding to the high speed FF / REW is not generated on the reel bases (1) and (2). Torque cross also occurs due to the gear train.

Therefore, as shown in FIG. 4, each reel stand
Various proposals have been made in which the dedicated DC reel motors (3) and (3) are connected to (1) and (2) (see Japanese Patent Publication No. 2-8383). The reel motor (3) has a stator coil (31) on the bottom surface.
It comprises a stator (30) provided with (31) and a rotor (32) which is rotatably supported on the chassis (7) so as to face the stator coil (31) and whose upper surface is magnetized. This magnetic recording / reproducing apparatus gives a predetermined drive voltage to the reel motor (3) on the take-up side during FF / REW, and sets the drive voltage of the reel motor (3) on the sending side to 0V or to the magnetic field. Tape (6)
In order to prevent the tape from slackening, a drive voltage in the tape winding side is supplied to the reel motor (3) on the sending side.

[0005]

[Problems to be Solved by the Invention] At the time of FF / REW,
Since the reel on the delivery side is pulled by the magnetic tape (6) to rotate, the number of rotations of the reel increases when the winding diameter of the reel on the delivery side becomes smaller. In this case, reel motor (3)
A back electromotive force occurs in the electromagnetic force generated by the back electromotive force.
It becomes the braking force of the reel. As a result, it hinders fast-forwarding and rewinding. As a measure against such a problem, the reel motor (3)
Open the stator coil (31) circuit of the reel motor (3)
It is also conceivable to electrically open the. In this state, since the counter electromotive current does not flow in the stator coil (31), braking of the reel by the counter electromotive force can be prevented.

However, the motor shaft (3
3) and mechanical load due to friction of bearings still exist, and the problem that the rotation speed of the delivery side reel decreases due to such load torque remains. This problem can be solved by increasing the torque of the reel motor (3) linked to the take-up reel stand, but the magnetic attraction of the rotor (32) and the winding of the stator coil (31) are increased. Therefore, the cost of the reel motor (3) is increased. The present invention is FF / RE
At the time of W, it reduces the load of sending reels.
The purpose is to achieve smooth high-speed driving.

[0007]

A tape speed control device detects a winding diameter ratio Rm of a sending side reel and a winding side reel from an FG pulse generated corresponding to the rotation of each reel motor (3). Connect to the diameter calculation unit (41) and the winding diameter calculation unit (41),
A delivery force control unit (51) is provided which outputs a drive voltage value corresponding to the winding diameter ratio Rm and positively rotates the reel motor (3) linked to the delivery side reel in the tape delivery direction. There is.

[0008]

In the present invention, the drive voltage corresponding to the winding diameter of the delivery side reel is supplied to the delivery side reel motor (3) to positively drive the reel motor (3) in the tape delivery direction. Since it is rotated in the direction of 1, the braking load is not applied to the delivery side reel as in the conventional case. Therefore, high-speed tape winding can be smoothly performed. Further, since the load on the delivery side is not given a rotational load, the tape tension can be lowered, and the damage to the tape can be alleviated even when the thin tape is wound at a high speed and delivered.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an example of the present invention will be described in detail with reference to the drawings. Reel stand (1) (2) on chassis (7)
The arrangement is the same as the conventional one (see FIG. 5). As shown in FIG. 4, reel motors (3) and (3), which respectively rotate and drive the reel stands (1) and (2), are provided below the reel stands (1) and (2), respectively. Motor shaft (33) protruding from 32) is on the reel stand
Fits (1) and (2). Both reel motors (3) (3) are electrically connected to a reel control microcomputer (hereinafter abbreviated as "reel control microcomputer") (4). In the following description, the reel stand (2) on the right side of FIG. 4 is called the T (take up) side, and the reel stand (1) on the left side of FIG. 4 is called the S (supply) side for convenience of explanation.

Each of the reel motors (3) and (3) is a direct current drive brushless motor, and an FG coil (not shown) is provided between the stator coils (31) and (31). Rotor
The induced current generated in the FG coil by the rotation of (32) is F
It is taken out as a G pulse. The structure for connecting the reel base and the reel motor (3) to each other is not limited to that shown in FIG. 4, and there are various structures, and the present invention can be applied to them.

FIG. 1 is a block diagram of the reel control microcomputer (4). Drive circuits (9) and (9) for supplying drive voltages to the T-side reel motor (3) and the S-side reel motor (3) are connected to and controlled by the reel control microcomputer (4). The FG pulse of each reel motor (3) (3) is input to the reel control microcomputer (4). The reel control microcomputer (4) is also connected to a system controller (8) which outputs a tape running mode signal, and the mode signal from the system controller (8) is used by the mode discriminating circuit () in the reel control microcomputer (4). 40) is input. The system controller (8) is connected to an operation button (not shown) provided on the front panel of the recording / reproducing apparatus.

In the reel control microcomputer (4), in addition to the mode discriminating circuit (40), a mode processing section (5), a winding diameter calculating section (41), cycle detecting circuits (42) (42), which will be described later, PWM (pulse width
Modulation circuit (43) (43) is arranged. The PWM conversion circuit (43) indicates the voltage to be supplied to the drive circuit (9) by the duty ratio, and the drive circuit (9) and the PWM conversion circuit (43)
A low-pass filter including a resistor R and a capacitor C is provided between them.

F from the T side and S side reel motors (3) (3)
The G pulse is input to the cycle detection circuits (42) and (42), respectively, and the cycle detection circuits (42) and (42) change the reel motor from the FG pulse.
The rotation cycle of (3) is detected. If the winding diameter of the magnetic tape 6 is large, the rotation cycle is long, and if the winding diameter of the magnetic tape 6 is small, the rotation cycle is short. This is because the winding diameter and the rotation speed of the reel motor (3) have an inversely proportional relationship as is well known. The outputs from both cycle detection circuits (42) and (42) are input to the winding diameter calculation unit (41). The winding diameter calculation unit (41) determines the winding diameter ratio Rm of both reels from the rotation cycle of the both reel motors (3) and (3).
And the winding state of the magnetic tape (6) can be known from the winding diameter ratio Rm. Here, the winding diameter ratio Rm means the S-side reel motor.
It refers to a dimensionless number obtained by dividing the rotation cycle of (3) by the rotation cycle of the T-side reel motor (3).

The mode processing section (5) includes a mode discrimination circuit (40).
Connected to the control signal transmission part (52) to which the signal from the device is input, the winding force control part (50) which outputs the voltage value to be supplied to the winding side reel motor (3), and the winding diameter calculation part (41) Then, a sending force control unit (51) that outputs a voltage value to be supplied to the sending side reel motor (3), and a rotation direction control unit (53) that instructs both reel motors (3) and (3) in the rotation direction. Equipped with. Two changeover switches are provided between the winding force control unit (50) and the feeding force control unit (51).
(54) and (54) are provided, and the changeover switches (54) and (54) are connected to the drive circuits (9) and (9) through the PWM conversion circuits (43) and (43), respectively. The changeover switches (54), (54) are for the control signal transmitter (5
It is switched by 2).

A memory (57) is provided in the delivery force control section (51), and a reel on the delivery side is provided in the table of the memory (57) with various winding diameter ratios Rm as addresses. motor
The drive voltage values V1 to Vn supplied to (3) are stored respectively (see FIG. 3). This drive voltage value is obtained in advance by actual measurement. First, a recording / reproducing device serving as a measurement standard is prepared, and a value obtained by dividing the maximum value R1 and the minimum value Rn of the winding diameter ratio Rm into n is calculated. Next, for each section of the winding diameter ratio Rm, the upper limit of the drive voltage that can rotate the reel motor (3) in the delivery direction to the extent that the magnetic tape (6) delivered from the reel on the delivery side does not loosen. The driving voltage value is obtained by actually measuring the value. Although a memory is also provided in the winding force control unit (50), even if a single drive voltage value is stored in the memory, the same as the delivery force control unit (51), The value of the drive voltage supplied to the reel motor (3) on the winding side may be stored by using various winding diameter ratios Rm as addresses. It is already disclosed in Japanese Patent Publication No. 2-8383 that the drive voltage value supplied from the winding force control unit (50) is changed according to the winding diameter ratio Rm.

The present invention is characterized in that the reel motor (3) on the delivery side is rotated in the delivery direction when the tape is wound, and the operation of each block will be described below by taking the FF as an example. At FF, the T side reel motor (3) is on the winding side,
The S-side reel motor (3) is on the delivery side. A 4-bit or 8-bit signal indicating that the magnetic tape 6 is fast-forwarded from the system controller 8 is supplied to the mode discriminating circuit 40. The mode discrimination circuit (40) uses the bit array of the signal
The signal indicating that the FF operation is performed is read, and the control signal transmission unit (52) is notified of that fact. Upon receiving the signal, the control signal transmission unit (52) switches the changeover switches (54) and (54), and the sending force control unit (51) causes the S side reel motor (3) to take up the winding force control unit (50). ) Are connected to the T-side reel motors (3), respectively.

The output from the mode discriminating circuit (40) is input to the rotation direction control unit (53) via the control signal transmission unit (52), and the rotation direction control unit (53) outputs each reel motor (3). ) To determine which direction to rotate each drive circuit (9) (9)
To communicate. Drive circuit linked to T-side reel motor (3)
(9) is a T-side reel motor (3) based on the voltage value input from the winding force control section (50) through the PWM conversion circuit (43).
To rotate. When the T-side reel base (2) rotates, the S-side reel base (1) and the S-side reel motor (3) are rotated by being pulled by the magnetic tape (6). The FG pulses from the reel motors (3) and (3) are input to the cycle detection circuits (42) and (42), and the winding diameter calculating unit (41) calculates the winding diameter ratio Rm as described above.

From the delivery force control section (51), the winding diameter ratio Rm
The drive voltage value corresponding to the
The drive circuit (9) connected to (3) rotates the S-side reel motor (3) in the delivery direction based on the drive voltage. Since the drive voltage is set in advance so that the magnetic tape (6) does not sag, the magnetic tape (6) will not be fed out too much.

The operation procedure during FF is shown in the flowchart of FIG. First, the mode discriminating circuit (40) discriminates the tape running mode (S1), and if it is the FF mode, the control signal transmitting section
The changeover switch (54) is switched (S2) so that the winding force control section (50) and the T side reel motor (3) are connected to each other (52).
The winding force control unit (50) determines the drive voltage of the T-side reel motor (3) (S3). The drive voltage may be a constant value as described above, or may be changed according to the winding diameter ratio Rm. Next, the winding diameter calculation unit (41) obtains the winding diameter ratio Rm from the FG pulse generated from both reel motors (3) and (3) as described above.
(S4). The delivery force control unit (51), based on the winding diameter ratio Rm,
The drive voltage value of the S-side reel motor (3) is called from the memory (57) (S5). Initially, both reel stands (1) (2)
When is stopped, no FG pulse is generated.
At this time, the delivery force control unit (51) sets the winding diameter ratio Rm to a virtual value, for example, 1 and advances the subsequent processing. As will be described later, when both reel motors (3) and (3) start to rotate and an FG pulse is generated, a drive voltage value based on the winding diameter ratio Rm is output.

The rotation direction control section (53) has a control signal transmission section (5
Based on the output from 2), the rotation directions of both reel motors 3 and 3 are determined (S6). The winding force control section (50) outputs the voltage determined in step S3 (S7), and the drive circuit (9) rotates the T-side reel motor (3). Next, the sending force control unit
(51) determines whether or not both reel stands (1) and (2) were initially rotating (S8), and the reel stands (1) and (2) were initially stopped, that is, the system controller (8). Signal from FF
If it is determined to be in the activated state, the output to the PWM conversion circuit (43) is stopped (S9), and it is determined whether or not a certain time has elapsed in this state (S10). After a certain period of time, the sending force control unit
(51) outputs the drive voltage value determined in step S5 (S
11), the drive circuit (9) rotates the S-side reel motor (3). When it is determined in step S8 that the FF is not started, the process proceeds to step S11, and the S-side reel motor
Rotate (3).

As described above, the reason why the S-side reel motor (3) is rotated after the elapse of a certain time after the T-side reel motor (3) is driven is to prevent the tape from loosening during the FF drive. Is. That is, when both reel motors (3) and (3) rotate at the same time, when the winding diameter of the S-side reel is large, the magnetic tape (6) delivered from the S-side reel is momentarily transferred to the T-side reel stand (2). This is because it may not be wound up. When the drive voltage is supplied to both reel motors (3) and (3), the process returns to step S1 and the operations up to step S11 are repeated. When the system controller (8) inputs a command signal for shifting or stopping to another mode, the process proceeds to step S12 and the processing to that effect is performed. In the above flow chart, step S6, step S2 and step S2
It may be provided between the three.

In this example, a drive voltage corresponding to the winding diameter of the S-side reel is supplied to the S-side reel motor (3) to positively rotate the reel motor (3) in the tape feeding direction. Therefore, unlike the prior art, no braking load is applied to the tape feeding. Therefore, FF can be smoothly performed at high speed. Further, since no rotational load is applied to the S-side reel, the tape tension can be lowered, and the damage to the tape can be alleviated even when the thin tape is wound at a high speed and delivered. In particular, the effect is great when high-speed FF is performed using a thin tape used for a digital VTR or the like. In the above example, the FF mode is described, but the same effect can be obtained in the REW mode. In this case, the S side reel stand (1) winds the magnetic tape (6), and the changeover switches (54) and (54) are turned to FF.
Needless to say, it switches in the reverse order of time.

The description of the above embodiments is for the purpose of illustrating the present invention and should not be construed as limiting the invention described in the claims or reducing the scope thereof. Further, the configuration of each part of the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made within the technical scope described in the claims.

[Brief description of drawings]

FIG. 1 is a block diagram of a reel control microcomputer.

FIG. 2 is a flowchart showing an operation in a reel control microcomputer.

FIG. 3 is a diagram showing a table of drive voltages of a delivery side reel motor corresponding to a winding diameter ratio.

FIG. 4 is a front view showing a mounting state of a reel stand and a reel motor on a chassis.

FIG. 5 is a plan view of a conventional recording / reproducing apparatus.

[Explanation of symbols] (1) Reel stand (2) Reel stand (3) Reel motor (6) Magnetic tape (9) Drive circuit (41) Roll diameter calculation unit (51) Sending force control unit

Claims (3)

[Claims] 1. A magnetic tape fitted to a cassette reel.
A pair of reel stands (1) and (2) for winding or sending (6),
Reel motor (3) for rotating each reel stand (1) (2) respectively
Corresponding to the rotation of the reel motor (3) and (3), the FG
Chassis (7) with FG pulse generator to generate pulses
In the above, each reel motor (3) is a tape speed control device connected to a drive circuit (9) that supplies a drive voltage to the reel motor (3). A winding diameter calculation unit (41) for detecting the winding diameter ratio Rm of the side reel, and a winding diameter calculation unit (41)
To output a drive voltage value corresponding to the winding diameter ratio Rm, and positively rotate the reel motor (3) linked to the delivery side reel in the tape delivery direction (51). )
Tape speed control device. 2. The tape speed control device according to claim 1, wherein the feeding force control section (51) has a built-in memory (57) in which a motor drive voltage value corresponding to the winding diameter ratio Rm is stored in advance. . 3. A magnetic tape fitted to a cassette reel.
A pair of reel stands (1) and (2) for winding or sending (6),
Reel motor (3) for rotating each reel stand (1) (2) respectively
(3) is provided on the chassis (7), and the winding diameter ratio Rm of the sending side reel and the winding side reel is detected from the FG pulse generated corresponding to the rotation of each reel motor (3), and the winding diameter The motor drive voltage corresponding to the ratio Rm is supplied to the reel motor (3) linked to the sending side reel stand,
A tape speed control method for positively rotating the reel motor (3) in the tape feeding direction.