JPH076460A - Tape protecting device for video tape recorder - Google Patents

Abstract

PURPOSE:To realize rapid detection and quick shift to succeeding actions by detecting the end of a tape by a sensor without pulling out the tape from a cassette. CONSTITUTION:When a leading pin 9 is rotated counterclockwise to get over a 1st moving position II, a sensor 15 is at a position shown by a chain line by a cam on an annular body 11, and is restored to an original position, on the contrary, in the midst of restoring action to the position II. When the pin 9 reaches a 2nd moving position III, a motor M1 is stopped by a switch S3. At the position III, the tape is laid on a cylinder 10 by specified amount, and recording and reproducing is performed. When a new cassette is loaded, the sensor 15 is opposed to the tape T between guides 2 and 3 in the cassette, so that the sensor 15 detects a leader part when the leader part is located on a supply reel side. The tape is moved to the position II, and a take-up reel is fast forwarded and moved for a fixed time, thereafter, the pin 9 is restored to a stop position I. Then, the leader part is removed from the detecting area of the sensor 15 so as to make a recorder in a standby state for next operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape protection device for a video tape recorder (VTR).

[0002]

2. Description of the Related Art In a conventional VTR in which an annular body having a tape guide pin is rotated around a cylinder to mount the tape on the cylinder, a take-up (one) reel is used to mount the tape in a cassette on the cylinder. The tape is unwound from the supply reel and the tape is not fed from the supply (other) reel to prevent the tape from sliding on the cylinder when loading or unloading the tape. Thus, in the VTR of the type that reels out or winds the tape from the take-up reel side, when loading an unused cassette and mounting the tape on the cylinder, the VTR has a leader portion of sufficient length for loading. Part of it is wound on the supply reel side and the tape cannot be completed unless there is a tape on the take-up reel side to complete the loading. There is a risk of pulling the tape away from.

By the way, as a VTR for solving the above-mentioned problem, there is Japanese Patent Laid-Open Publication No. 57-162146, which detects the end of the tape by detecting whether or not it is the end of the tape after pulling out the tape from the cassette. In this case, the tape is run at a high speed in the opposite direction, and then the tape loading operation is performed.

[0004]

In the above configuration, since the tape end is detected while the tape is pulled out from the cassette, it takes time to detect the tape end, which allows the next operation to move quickly. The drawback was that it was not possible. Further, when the tape end is detected, it is configured to run at high speed until it is detected that it is not the end of the tape, and the high speed running is continued for another 2 seconds.
There is a drawback that the circuit configuration becomes complicated.

[0005]

SUMMARY OF THE INVENTION The present invention seeks to prevent such drawbacks, and when the tape end sensor detects the end of the tape when the tape is in the cassette,
One of the reels is driven in the tape winding direction for a fixed time required to wind the tape end portion at least by an amount required for loading into the cylinder.

[0006]

When the tape end sensor detects the tape end, one reel is driven in the winding direction of the tape only for a certain period of time so that the tape end is wound at least the amount necessary for loading into the cylinder. Therefore, the transition to the next operation can be performed quickly, and the operation with a poor mechanical rhythm,
Also, it is possible to prevent the tape from being damaged.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the device of the present invention will be described with reference to the illustrated embodiments. FIG. 1 schematically shows the device of the present invention.
(1) is a cassette, which is provided with tape guides (2) and (3) on which a magnetic tape (T) is stretched, and when set on a VTR, supply and take-up reels (both not shown) are respectively A tension pin (8) and a leading pin (9) described later, which are placed on the supply reel base (4) and the take-up reel base (5), and which are provided at the end of the arm (7) rotatable by the support shaft (6). It is designed to penetrate inside the tape loop.

(10) is a cylinder having a rotary head for guiding the tape, and (11) is a tape for winding the tape in the cassette (1) around the cylinder circumferential surface, and a leading guide pin (for releasing the winding). It is an annular body that guides 9). The rotation of the annular body (11) is controlled in the counterclockwise (loading) direction or the clockwise (unloading) direction by the motor (M1), and at the time of rotation, a cam (not shown) provided on the annular body (11) In the process in which the leading pin (9) reaches the first moving position (II) from the illustrated initial position (I), the brake (12) biased by the take-up reel base (5) is released and the tape guide (2) is released. ) (3) The tape which is stretched straight is pulled out by the tension pin (8) as shown by the broken line (T ') in the figure. This first movement position (II)
Is a position that allows fast forward or rewind of the tape, and when these commands are given, the brake (13) of the supply reel base (4) is released and the motor (M2) is driven at high speed to execute each operation. It

Recognition of the initial position and the second position (I) and (II) of the leading pin (9) is controlled by an actuator (not shown) provided on the annular body (11). S1) (S2). (14) is a tape end sensor provided on the supply reel stand (4) side, and (15) is a tape end sensor provided on the take-up reel stand (5) side, both of which are magnetic and non-magnetic parts of the tape (T) ( (Leader part)
Are known in the art by detecting their electrical conductivity. The sensor (15) is arranged at the open end of the arm (17) which rotates about the fulcrum (16), and the sensor is attached to the annular body (1).
It is configured to reciprocate between the two positions shown in the drawing in accordance with the rotation of 1).

That is, when the leading pin (9) is rotated counterclockwise beyond the first movement position (II), the sensor (15) is arranged at the chain line position by the cam on the annular body (11). On the contrary, it is configured to be returned to the illustrated position during the returning operation to the first movement position (II). When the leading pin (9) is brought to the second movement position (III), the third switch (S3) is activated to stop the motor (M1). At the second moving position, a predetermined amount of tape is mounted on the cylinder (10) to allow the recording or reproducing operation.

In this VTR, when a new cassette is loaded, the sensor (15) is arranged to face the tape (T) stretched between the tape guides (2) and (3) in the cassette. If the reader section is arranged on the supply reel side, the sensor (15) detects this. When the VTR of the present invention detects this, the tape is transferred to the take-up reel side in the following procedure, the leader section is removed from the detection area of the sensor (15), and the next operation is awaited.

First, the tape in the cassette is transferred to the first transfer position (II), and then the take-up reel is fast-forwarded and transferred at the first transfer position for a certain period of time, and then the leading pin is returned to the initial position (stop position). Let

FIG. 2 is a circuit for creating a gate signal for driving the motors (M1) and (M2) to execute such an operation, and FIG. 3 is a time chart for explaining the operation. 4 and 5 are motors for driving an annular body (M
It is a drive circuit diagram of 1) and a reel drive motor (M2).

In FIG. 2, the terminal (20) is a sensor (1
5) The first input terminal for receiving the output, (21) is the second input terminal for receiving the output of the second switch (S2), and (22) is the first
The third input terminal receives the output of the switch (S1).
The output of the sensor (15) is output by a controller (not shown) so as to give an effective signal to the first input terminal (20) only when the leading pin (9) is present at the first, second or third position. Controlled. A signal a from the first input terminal (20) passes through a monostable multivibrator (23) (hereinafter, the monostable multivibrator is referred to as MM) to an RS flip-flop (24) (hereinafter, the RS flip-flop is referred to as FF). The signal C given to the set terminal and from the second input terminal (21) is given to the reset terminal of the FF (24).

Therefore, the gate signal d for driving the motor (M1) in the positive (loading) direction can be derived as the output of the FF (24). During the high period of the gate signal d, the transistors (41) (44) shown in FIG.
Becomes conductive, and the motor (M1) rotates in the forward direction. As a result, the annular body (11) rotates to the first movement position (II) and stops.

The outputs a and c of the first and second input terminals (20) and (21) are applied to the gate (25) to generate the signal e.
This signal e is given to the second MM (26) whose metastable time is set to 650 ms, and drives the reel motor (M2) in the forward direction (winding the tape on the take-up reel) as the output of this second MM. The gate signal f to be derived is derived. During the high period of the gate signal f, the transistor (5
1) (54) becomes conductive and the motor (M2) rotates in the forward direction.

Therefore, the take-up reel is controlled to rotate in the forward direction for 650 msec, and the leader portion of the tape is completely taken up by the take-up reel. This gate signal f is given to the set terminal of the second FF (28) through the third MM (27), while the first switch (S1) output h is given to the reset terminal of the second FF (28). , This second FF (2
A gate signal i for returning the annular body (11) to the initial position (I) is derived as an output of 8). During the high period of the gate signal i, the transistors (43) and (42) shown in FIG.
Is turned on to rotate the motor (M1) in the reverse direction, and the transistors (51) and (52) shown in FIG. 5 are turned on to rotate (M2) in the forward direction. As a result, the annular body (11) is returned from the first transfer position (II) to the initial position (I), and the tape (T ') is wound on the take-up reel.
The VTR is set to stop mode. Then, the VTR waits to accept the general operation mode.

[0018]

According to the present invention, since the end portion of the tape is detected without pulling out the tape from the cassette, the detection is fast and the subsequent operations can be rapidly shifted.
Further, the winding of the tape is set to a fixed time required for winding the tape amount required for loading, so that the configuration is extremely simple.

When the cassette is loaded in the VTR,
If the tape edge sensor operates, the reel is automatically driven in the tape winding direction for a certain period of time, so it is possible to mount the tape on the cylinder without performing this process. It is practical because it can prevent accidents that may occur when it is executed.

[Brief description of drawings]

FIG. 1 is a schematic view showing a device of the present invention.

FIG. 2 is a gate signal generation circuit diagram of the device of the present invention.

FIG. 3 is a timing chart showing the operation of the circuit of FIG.

FIG. 4 is a drive circuit diagram of an annular body drive motor.

FIG. 5 is a drive circuit diagram of a reel drive motor.

[Explanation of symbols]

 1 ... Cassette 4 ... Supply reel stand 5 ... Winding reel stand 10 ... Cylinder 15 ... Tape end sensor 11 ... Annular body

Claims (1)

[Claims] 1. A tape protection device for a video tape recorder, wherein a tape in a cassette is unwound from one reel and mounted on a cylinder, and a tape end sensor arranged to face the tape in the cassette and the tape in the cassette. A tape which, when the tape end sensor detects the tape end in a certain state, drives the reel for a fixed time required to wind the tape end at least an amount necessary for loading into a cylinder. A tape protection device for a video tape recorder, comprising a transfer control means.