JP3531318B2 - Magnetic tape counter - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape counter effective for use in a magnetic recording / reproducing apparatus and the like.

[0002]

2. Description of the Related Art In recent years, a magnetic recording / reproducing apparatus, particularly a VTR, is generally provided with a function of counting the amount of tape transfer, displaying a numerical value, and displaying time. Is also an important factor.

A conventional magnetic tape counter will be described below. FIG. 5 is a schematic view of the mechanical system of a VHS type VTR. 1 is a head cylinder, 2 is a voice control head (hereinafter control head), 3 is a pinch roller, and 4 is a capstan which is directly connected to a capstan motor and driven. Reference numeral 5 is a supply side reel (hereinafter, S reel), and 6 is a winding side reel (hereinafter, T reel), both of which are housed in a cassette case. In the VHS format, a control pulse is recorded at the lower end of the tape, amplified by the control amplifier 7, processed by the microcomputer 8 having a count display processing circuit, and displayed on the display unit 9 for time.

The microcomputer 8 has not only a count display process but also a mechanism control function and a rotation control function for the head cylinder and capstan motor. Further, the S and T reels 5 and 6 rotate using a capstan motor as a drive source via a clutch, a gear and a belt. The tape is transferred in the direction of arrow A for recording or reproduction, but it is also possible to rotate the capstan motor in the reverse direction to transfer the tape in the reverse direction for reproduction.

FIG. 6 is a simplified diagram of FIG. 5 showing the case where the winding diameter of the S reel 5 is large and the T side 6 is small. FIG. 6A shows the tape transfer direction in the forward direction, and FIG. The transfer direction of the tape has changed, (c) shows the stable state in the reverse direction, and (d) shows the state in which the transfer direction of the tape has changed again from the reverse direction to the forward direction.
In (b), the S-reel diameter is large, that is, the moment of inertia is large, and the drive sources of the capstan 4 and the S-reel 5 at this time are the same motor, that is, the rotation of the S-reel 5 having large inertia is momentarily due to the capstan motor. As a result, the tape becomes slack between the pinch roller 3 and the guide post 10 and the tape does not come into contact with the control head 2, resulting in a missing reproduction control pulse. This slack becomes more significant as the S reel diameter increases. (D) is the opposite of (b), and the rotation on the S side is momentarily delayed while the tape transport direction changes in the direction of arrow B, but in this case the slack as in (b) does not occur.

In FIG. 7, the winding diameter of the reel is opposite to that in FIG. 6, and in FIG. 7B, since the inertia moment on the S side is small, the tape is wound normally, so that slack does not occur.

On the other hand, in (d) , the rotation on the T side is delayed for a moment, but the slack only occurs between the capstan and the T side, and the control pulse is correctly reproduced.

[0008]

However, in the above-described conventional structure, as shown in FIG. 6B, when the moment of inertia on the S reel side becomes large, the rotation of the S reel 5 having a large inertia momentarily slows down. There is a problem that slack occurs between the pinch roller 3 and the guide post 10 and the tape does not come into contact with the control head so that the reproduction control signal is lost.

An object of the present invention is to solve the above problems and to provide a highly accurate magnetic tape counter by reducing the tape slack and correcting the reproduction loss of the control pulse due to the remaining slack.

[0010]

To achieve this object, a magnetic tape counter of the present invention comprises a reel stand for supporting and rotating a reel of a cassette tape, a capstan for pinching and transferring the tape, a pinch roller and a pinch. It comprises a mechanism for moving the roller to start and stop the tape transfer, a control head, and means for counting and correcting the reproduction control pulse and displaying the numerical value.

With this configuration, the loss of the reproduction control pulse due to the slack caused by the change in the tape transport direction is reduced, and the loss of the number of the reproduction pulses due to the remaining slack is corrected to obtain a highly accurate magnetic tape counter.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claims 1 to 3 of the present invention is a magnetic tape counter for counting a control signal reproduced by a control head to measure a transfer amount of a magnetic tape, which is a cassette tape. Reel base for rotating the reel, a capstan and a pinch roller for nipping and transferring the magnetic tape, a computing means for counting and computing the control signal, and a display for displaying the numerical value counted by the computing means. Means for absorbing the tape slack caused by the moment of inertia of the magnetic tape reel after the transfer direction of the magnetic tape has been switched, by absorbing the pinch roller in a stop mode in which the pinch roller separates from the magnetic tape, The control pulse number is the tape transfer amount due to the moment of inertia of the tape reel in the roller stop mode. Counted, by this value is proportional to the magnetic tape slack amount, has the effect of correcting the lack of reproduction control pulse by sagging.

(Embodiment 1) An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows a method for minimizing the slack of the magnetic tape in FIG. 4 and compensating for the reproduction loss of the control pulse.

FIG. 1 shows a case where the S reel winding diameter is large.
In (a), the magnetic tape is transported in the direction of arrow D.
(B) shows immediately after changing the magnetic tape in the direction of arrow E. The S-reel 5 has a large moment of inertia, and the driving force of the capstan motor causes slack in the vicinity of the control head 2 due to the transmission delay of the belt and gear. (C) is a view in which the pinch roller 3 is separated from the magnetic tape. Since the transfer of the magnetic tape is about to stop, the slack caused by winding the magnetic tape around the S reel 5 is eliminated. At this time, since the moment of inertia of the T reel 6 is small, the T reel 6 is instantaneously stopped immediately after the pinch roller 3 is separated from the magnetic tape. In FIG. 2A, the slack is completely eliminated, and in FIG. 2B, the pinch roller 3 again comes into close contact with the magnetic tape and the normal reverse transfer is performed. (C) is a diagram in which the magnetic tape has changed again in the direction of the arrow D. Although the rotation of the S reel 5 is delayed, the magnetic tape is fed in the forward transfer, which does not cause slack.

FIG. 3 shows the case where the S reel winding diameter is small.
In (a), the magnetic tape is transported in the forward direction. (B)
Shows the state immediately after changing the transport direction of the magnetic tape to the arrow E direction. The S reel 5 has a small moment of inertia and is shown in FIG. 1 (b).
The slack like does not occur. (C) is a diagram in which the pinch roller 3 is separated from the magnetic tape, and the transfer of the magnetic tape is about to be stopped, but the S reel is wound fast, so that slack does not occur. In (d), since the moment of inertia of the T reel 6 is large, the tape slackens in contrast to the case of FIG. 2 (a), but in reality, the S reel is wound fast, and the reel on the side wound again. Has a soft brake to maintain the tension of the magnetic tape and does not have a large slack. (Compensation for missing the reproduction control pulse due to the slack of the magnetic tape generated here will be described later.) In (b), the pinch roller 3 again comes into close contact with the magnetic tape, and normal reverse transfer is performed. (C) is a diagram in which the magnetic tape has changed again in the direction of arrow E. Although the rotation is delayed because the moment of inertia of the T reel 6 is large, the tape does not become slack near the control head.

As described above, according to the present embodiment, the tape slack caused by the moment of inertia of the magnetic tape reel immediately after the transfer direction of the magnetic tape is changed causes the pinch roller to separate from the magnetic tape. Absence of the reproduction control pulse can be suppressed as much as possible by absorbing it by setting the traveling stop position mode of.

The compensation of the missing reproduction control pulse due to the slack of the magnetic tape in FIGS. 1 to 4 will be described.

In FIG. 2 (a), since the moment of inertia of the T reel 6 is small, the tape transfer amount at this time when the pinch roller 3 is away from the magnetic tape is small, and the reproduction control pulse is small including the missing number. On the other hand, in FIG. 4 (a), since the moment of inertia of the T reel 6 is large, the tape transfer is continued due to inertia immediately after the pinch roller 3 is separated from the magnetic tape, and the reproduction control pulse including the missing number is also shown in FIG.
Big compared to.

The number of missing reproduction control pulses is T
It can be seen that it is proportional to the moment of inertia of Rule 6. Since the control pulse reproduced when the pinch roller 3 is separated from the magnetic tape is proportional to the moment of inertia of the T reel 6, (Equation 1) is established.

[0020]

[Equation 1]

K and C are constants and are proportional coefficients of N _R.CTL N _F.CTL .
Actually measuring the _R.CTL, N _F.CTL is by measuring the number of times the error of the measured value and the ideal value of the counter value after F, K, C can be determined. 1 (c), 2 (a), 3 (c), 4
In (a), N _R.CTL is measured and counted, and after calculating a mathematical expression by the microcomputer in the display processing circuit, N _F.CTL is calculated,
By adding to the actual reproduction control pulse at the stage of FIGS. 2B and 4B, the correction of the missing portion is completed.

FIG. 2 shows that the tape running is stable.
Similar results can be obtained by subtracting from the actual reproduction control pulse in the stages of (c) and FIG. 4 (c).

As described above, according to this embodiment, the pinch roller is separated from the magnetic tape immediately after the transfer direction of the magnetic tape is changed to a mode in which the tape transfer is stopped. At this time, the tape is caused by the moment of inertia of the tape reel. To increase the accuracy of the magnetic tape counter by counting the transfer amount as the number of control pulses, and adding the calculated value to the control pulse actually played as the correction value for the missing playback control pulse due to slack in the magnetic tape. Will be possible.

[0024]

As described above, according to the present invention, the pinch roller separates the tape slack caused by the moment of inertia of the magnetic tape reel after the switching direction of the magnetic tape from the magnetic tape transfer. It is absorbed by setting the stop mode, and the transfer amount due to the moment of inertia of the tape reel in the stop position mode of the pinch roller is counted as the number of control pulses, and the calculated value is the reproduction control pulse due to the slack of the magnetic tape that cannot be absorbed. The accuracy of the magnetic tape counter can be increased by using it as a correction value for the loss of the tape.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of a first embodiment of a magnetic tape counter of the present invention.

FIG. 2 is a schematic diagram showing the configuration of Embodiment 1 of the magnetic tape counter of the present invention.

FIG. 3 is a schematic diagram showing the configuration of the first embodiment of the magnetic tape counter of the present invention.

FIG. 4 is a schematic diagram showing the configuration of Embodiment 1 of the magnetic tape counter of the present invention.

FIG. 5 is a perspective view showing the configuration of a VHS format VTR.

FIG. 6 is a schematic diagram showing a configuration of a conventional magnetic tape counter.

FIG. 7 is a schematic diagram showing a configuration of a conventional magnetic tape counter.

[Explanation of symbols]

1 head cylinder 2 control head 3 pinch rollers 4 capstan 5 supply reels 6 take-up reel 7 Control amplifier 8 microcomputer 9 Display 10 Guide post 11 Guide post

Claims (3)

(57) [Claims] 1. A magnetic tape counter for counting a control signal reproduced by a control head to measure a transfer amount of a magnetic tape, comprising a reel stand for rotating a reel of a cassette tape and a magnetic tape sandwiched between the reel base. A magnetic tape that includes a capstan and a pinch roller to be transferred by a moving unit, a computing unit that counts and computes the control signal, and a display unit that displays the numerical value counted by the computing unit.
Immediately after switching the transfer direction of the
A magnetic tape counter characterized by being separated from the magnetic tape. 2. A control reproduced by a control head.
A magnet that counts the roll signal and measures the transfer amount of the magnetic tape.
An air tape counter, which is a reel stand for rotating a reel of a cassette tape, and a capstan and a pin for holding and transferring the magnetic tape.
Bei and Nchirora, calculating means for calculating by counting the control signals, and display means for displaying the numerical value counted by said calculating means
The pinch immediately after switching the magnetic tape transfer direction.
Separate the roller from the magnetic tape and
At the moment of inertia of the reel of the cassette tape.
The tape transfer amount is counted as the number of control pulses,
The numerical value after the calculation of the count value is reproduced by the magnetic tape sag
As a correction value for the missing control pulse, it is actually reproduced.
A magnetic tape counter characterized by adding to a control pulse that is generated. 3. A reproduction control pulse based on the calculation
Correction value NF. CTL is the transfer direction of the magnetic tape
When the pinch roller is separated from the magnetic tape and operates to stop the transfer of the magnetic tape immediately after switching, the magnetic tape is further transferred by the inertia of the reel, and the control signal reproduced at this time is counted, This count value is NR. If CTL, NF. CTL = KxNR. The magnetic tape counter according to claim 2 , wherein the error correction is performed by using CTL + C (K and C are constants) as a correction value.