JP2660449B2 - Magnetic recording / reproducing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording and reproducing apparatus, and more particularly to a magnetic recording and reproducing apparatus having an improved magnetic tape automatic stop function.

[Related Art] A magnetic recording / reproducing apparatus using a magnetic tape as a recording medium generally has a function of automatically stopping the running of the magnetic tape when the magnetic tape is wound up to the end. This function is provided in order to prevent the magnetic tape from being cut even after the magnetic tape has been wound up to the end, thereby preventing the magnetic tape from being cut.

Some current magnetic recording / reproducing devices optically detect the end of the magnetic tape and stop the running of the magnetic tape. FIG. 4 is a partial schematic block diagram of a video tape recorder which is an example of such a magnetic recording / reproducing apparatus. FIG. 4 shows a tape running system for running the magnetic tape. Hereinafter, the automatic operation of stopping the magnetic tape of the conventional video tape recorder will be described with reference to FIG.

A cassette 100 inserted into a video tape recorder during recording and playback includes a supply-side reel 1 and a take-up reel 2, and a magnetic tape 3 wound around these reels. When the cassette 100 is inserted into the video tape recorder and recording or playback is performed, the magnetic tape 3
Is pulled out of the cassette 100 and is applied to the rollers 106. Then, a capstan 104 arranged so as to hold the magnetic tape 3 between the pinch roller 102 and a capstan motor 106
It is driven and rotated by. Thus, the magnetic tape 3 is wound around the rotating drum 110 at a predetermined angle, and runs along the rollers 106. A video head (not shown) for reading a video signal from the magnetic tape 3 is attached to a peripheral portion of the rotating drum 110. The magnetic tape 3 runs,
In addition, when the rotating drum 110 rotates, the video head reads a video signal from the magnetic tape 3.

During recording and playback, the magnetic tape 3 is caused to run along the rollers 106 in this manner (loading state).
However, when fast-forwarding and rewinding are performed without reproducing, the magnetic tape 3 runs off the roller 106 as shown by the broken line 7 (unloading state).

Now, in order to detect that the magnetic tape 3 has been wound up to the end on the supply reel 1 or the take-up reel 2,
A light emitting diode (hereinafter, referred to as an LED) 4 and an end sensor 5 and a start sensor 6 are provided. The end sensor 5 is arranged near the magnetic tape outlet on the supply reel 1 side of the cassette 100, facing the surface of the magnetic tape 3 that has been taken out. Similarly, the start sensor 6 is arranged near the magnetic tape outlet on the take-up reel side of the cassette 100 so as to face the surface of the magnetic tape 3 taken out. The LED 4 emits light from the end sensor 5 of the magnetic tape 3.
And, it is arranged at a position where it is irradiated on the part facing the start sensor 6. Each of the sensors 5 and 6 includes a photoelectric conversion element such as a light receiving transistor.

A general magnetic tape has a structure in which a brown or black magnetic layer is formed on a transparent base film. However, both ends of the magnetic tape are transparent without this magnetic layer formed, and transmit light. This transparent part is called a leader part. In the conventional video tape recorder, the running of the magnetic tape is automatically stopped using this leader portion.

The LED 4 constantly emits light while the magnetic tape 3 is running. The light emitted from the LED 4 is applied to a surface of the magnetic tape 3 not facing the sensors 5 and 6.

At the time of fast forward (playback), normal playback and recording,
The supply reel 1 and the take-up reel 2 rotate in the direction of the arrow in the drawing, and as a result, the magnetic tape 3 is taken up from the supply reel 1 to the take-up reel 2.

When the portion of the magnetic tape 3 on which the magnetic layer is formed is sent from the supply reel 1, the portion of the magnetic tape 3 facing the end sensor 5 does not always transmit light. Therefore, the light emitted from the LED 4 is not applied to the end sensor 5. However, when the leader portion at the end of the magnetic tape 3 is sent from the supply reel 1 and travels to a position facing the end sensor 5, the light emitted from the LED 4 passes through the leader portion and irradiates the end sensor 5. Is done. The end sensor 5 converts this light into an electric signal,
The converted electric signal is provided to the control unit 108.

Control unit 108 stops capstan motor 106 in response to receiving the electric signal from end sensor 5. As a result, the rotation of the capstan 104 is stopped, and the running of the magnetic tape 3 is stopped.

Therefore, at the time of normal reproduction and normal recording, the end sensor 5 detects the end of the magnetic tape 3 at the time when all the recorded contents of the magnetic tape 3 are read and when the video signal is recorded until the end of the magnetic tape 3. When the leader portion is detected, the running of the magnetic tape 3 is stopped. In addition, in response to the end sensor 5 detecting the end of the magnetic tape 3, the control unit 108 reverses the rotation direction of the capstan 104 and moves the magnetic tape 3 from the take-up reel 1 to the supply reel 1. To be wound up, capstan motor 10
The rotation direction of 6 may be reversed. In other words, in this case, the magnetic tape 3 is automatically rewound to the supply reel 1 when the recording or recording of the video signal on the magnetic tape 3 is completed.

Similarly, at the time of reverse reproduction, rewinding, and the like, the supply-side reel 1 and the take-up reel 2 rotate in directions opposite to the arrows in the figure. As a result, the magnetic tape 3 is sent out from the take-up reel 2 and taken up on the supply reel 1. The portion of the magnetic tape 3 having a magnetic layer on the surface is the take-up reel 2
, The portion of the magnetic tape 3 facing the start sensor 6 does not always transmit light. Therefore, since the light emitted from the LED 4 is not irradiated on the start sensor 6, no electric signal is output from the start sensor 6. However, when the magnetic tape 3 was almost wound on the supply-side reel 1 and the leader portion at the start end of the magnetic tape 3 was sent from the winding-side reel 2 and traveled to the position facing the start sensor 6, the LED 4 emitted the light. The light passes through the reader portion and irradiates the start sensor 6. The start sensor 6 converts the light into an electric signal and supplies the converted electric signal to the control unit 108.

Control unit 108 stops capstan motor 106 in response to receiving the electric signal from start sensor 6.

Thus, at the time of reverse reproduction or rewinding, the traveling of the magnetic tape 3 is automatically stopped in response to the start sensor 6 detecting the leader portion at the start end of the magnetic tape 3.

[Problems to be Solved by the Invention] In a conventional video tape recorder in which the end of the magnetic tape is optically detected and the running of the magnetic tape is stopped or rewinding is started at the end of winding of the magnetic tape, The light transmitting portion of the tape is detected by the photoelectric conversion element.

Originally, the light transmitting portion of the magnetic tape is only the reader portion. However, the magnetic layer of the magnetic tape may be damaged for some reason, and the magnetic layer may have a portion where the transparent base film is exposed due to peeling or removal of the magnetic layer.

In such a case, when the exposed portion travels to a position facing the end sensor 5 or the start sensor 6 in FIG. 4, light emitted from the LED 4 passes through the exposed portion and passes through the end sensor 5 or the start sensor 6. Is irradiated. Then, the end sensor 5 or the start sensor 6
Operates in the same manner as when the light of the LED 4 is received via the reader portion, and outputs an electric signal to the control unit 108.

However, the control unit 108 does not have a function of determining whether the detection results of the end sensor 5 and the start sensor 6 are correct. As a result, even if an exposed portion other than the leader portion is erroneously detected by the end sensor 5 or the start sensor 6, the control unit 108 determines that the winding of the magnetic tape 3 has been completed and stops the running of the magnetic tape 3, For example, the rewinding of the magnetic tape 3 is started.

As described above, in the conventional video tape recorder, when the magnetic tape has a flaw or the like, the photoelectric conversion element for detecting the end of the winding of the magnetic tape detects a portion other than the leader portion, and the magnetic tape is actually wound. There is a possibility that the running of the magnetic tape is stopped or the running in the reverse direction is started even though it is not finished. If such a phenomenon occurs during recording, the video signal supplied to the video tape recorder after this "stop" is not recorded. Also, if such a phenomenon occurs during reproduction, the recorded contents of the magnetic tape after the exposed portion causing the "stop" will not be reproduced.

Therefore, an object of the present invention is to solve the above-mentioned problems, and to accurately control the running state of the magnetic tape at the end of winding of the magnetic tape regardless of the state of the surface of the magnetic tape. An object of the present invention is to provide a recording and reproducing device.

Means for Solving the Problems In order to achieve the above object, a magnetic recording / reproducing apparatus according to the present invention comprises a means for running a magnetic tape having a transparent portion, and a magnet running by the running means. Detecting means for optically detecting a transparent portion of the tape, calculating means for calculating a physical quantity corresponding to the amount of the magnetic tape traveled by the traveling means by a predetermined calculation, and transparency of the magnetic tape detected by the detecting means The position of the part
By confirming with the running amount of the magnetic tape corresponding to the physical amount calculated by the calculating unit at the time of the detection, the running unit is controlled based on the physical amount calculated by the calculating unit and the detection output of the detecting unit. Controlling means.

[Operation] As described above, the magnetic recording / reproducing apparatus according to the present invention includes the means for calculating the traveling amount of the magnetic tape in addition to the means for detecting the transparent portion of the magnetic tape.

Then, the position of the transparent portion of the magnetic tape detected by the detecting means is confirmed by the running amount of the magnetic tape corresponding to the physical quantity calculated by the calculating means at the time of the detection. The traveling means is controlled based on both the physical quantity and the detection output of the transparent portion detection means. Therefore, the running state of the magnetic tape can be controlled in accordance with two pieces of information at the same time: the detection output of the detecting unit for detecting the transparent portion and the physical amount corresponding to the tape running amount calculated by the calculating unit.

FIG. 1 is a schematic block diagram showing the configuration of a magnetic tape traveling system in a video tape recorder according to one embodiment of the present invention. 2 and 3 are a flowchart and a functional block diagram, respectively, showing the operation of the microcomputer 8 in the tape running system of this embodiment. Hereinafter, the configuration and operation of the tape running system of the present embodiment will be described in detail with reference to FIGS.

Referring to FIG. 1, this tape running system differs from that of the conventional video tape recorder shown in FIG. 4 in that a magnetic tape 3 wound around a supply reel 1 together with an end sensor 5 and a start sensor 6 is provided. And a microcomputer (microcomputer) 8 which receives as input the length of the magnetic tape 3 detected by the remaining amount calculator 11 and the detection outputs of the sensors 5 and 6.

The remaining amount calculation unit 11 measures the rotation cycle T of the supply-side reel 1 and the take-up reel 2, and calculates a predetermined value based on the measured value T, the hub diameter R of the supply-side reel 1, and the thickness d of the magnetic tape 3. The length of the magnetic tape 3 wound on the supply reel 1 is detected by a well-known calculation method of performing the following. This detection result is used as the length of the magnetic tape 3 that has not yet been wound on the take-up reel 2 (hereinafter, this is referred to as the remaining tape amount).
To the input terminal 12. According to the known calculation method, when the running speed of the magnetic tape 3 is represented by V, the remaining tape amount L _S is represented by the following equation, for example.

The end sensor 5 and the start sensor 6 are respectively constituted by NPN type light receiving transistors Q1 and Q2 provided with emitters. The detection outputs of the end sensor 5 and the start sensor 6 are input to the input terminals 9 and 10 of the microcomputer 8 via the detection output converter 15, respectively.

The detection output converter 15 includes a PNP transistor Q3 whose collector is connected to the input terminal 9 of the microcomputer 8, a resistor R1 provided between the base of the transistor Q3 and the collector of the transistor Q1, and a resistor R2. A constant reference voltage + B is applied to the emitter of transistor Q3. The resistor R2 is connected to the collector of the transistor Q1, and the reference voltage + B
Is supplied as a drive voltage to the transistor Q1. The detection output converter 15 is further provided between the collector of the transistor Q2 and the base of the transistor Q4, and a PNP transistor Q4 having a collector connected to the input terminal 10 of the microcomputer 8 and an emitter receiving the reference voltage + B. Resistance R3
And a resistor R4. The resistor R4 is connected to the collector of the transistor Q2 and supplies the reference voltage + B to the transistor Q2 as a drive voltage.

When the transparent portion of the magnetic tape 3 travels to a position facing the end sensor 5 when the magnetic tape 3 travels, the end sensor 5 is irradiated with light emitted from the LED 4. As a result, the transistor Q1 is turned on, and in the detection output converter 15, the base voltage of the transistor Q3 drops due to the emitter potential (that is, the ground potential) of the transistor Q1. When the transistor Q1 is in the OFF state, the base voltage of the transistor Q3 has been raised to a high level by the reference voltage + B. Therefore, when the transistor Q1 is in the OFF state, the signal is not applied to the input terminal 9 of the microcomputer 8 because the transistor Q3 is also in the OFF state. However, transistor Q1 is ON
In this state, the base voltage of the transistor Q3 drops, so that the transistor Q3 is turned on. As a result, the reference voltage + B is applied to the input terminal 9 via the transistor Q3.

Similarly, when the magnetic tape 3 travels and the transparent portion of the magnetic tape 3 travels to a position facing the start sensor 6, the light emitted from the LED 4 is applied to the start sensor 6. As a result, the transistor Q2 is turned on, and in the detection output converter 15, the base voltage of the transistor Q4 drops due to the ground potential. Transistor Q2
When in the OFF state, the transistor Q4 has its collector voltage pulled up to a high level by the reference voltage + B. Therefore, when the transistor Q2 is in the OFF state, the transistor Q4 is also in the OFF state. Therefore, no signal is applied to the input terminal 10 of the microcomputer 8. However, when the transistor Q2 is turned on, the transistor Q4 is turned on, so that the reference voltage + B is applied to the input terminal 10 via the transistor Q4.

As described above, the high voltage is applied to the input terminal 9 of the microcomputer 8 only when the light of the LED 4 is irradiated to the end sensor 5, and the input terminal of the microcomputer 8 is only applied when the light of the LED 4 is irradiated to the start sensor 6. High voltage is applied to 10. Therefore, the microcomputer 8 can determine whether or not the end sensor 5 or the start sensor 6 has been irradiated with the light of the LED 4 by determining the potential levels of the input terminals 9 and 10. On the other hand, to the input terminal 12 of the microcomputer 8, information indicating the remaining amount of the tape is input from the remaining amount calculator 11. The microcomputer 8 performs the following determination operation and control operation for the running of the magnetic tape 3 based on the information given to these input terminals 9, 10, and 12.

Referring to FIG. 2, when the running of the magnetic tape 3 is started, the microcomputer 8 first determines in step S1 the end sensor 5 or the start sensor 6 based on the level of the potential applied to the input terminals 9 and 10. It is determined whether or not any of the above has been irradiated with the light of the LED 4. As a result, when it is determined that there is an optical input to either the end sensor 5 or the start sensor 6, the microcomputer 8 determines in step S2 the magnetic tape 3 based on the remaining tape information supplied to the input terminal 12. Is completely wound on either the supply-side reel 1 or the take-up reel 2. That is, in the processing step S2, it is determined whether or not the light input to the end sensor 5 is due to the fact that the leader portion at the end of the magnetic tape 3 has traveled to the position facing the end sensor 5, It is determined whether or not the light input is really due to the start portion of the magnetic tape 3 having traveled to the position facing the start sensor 6. If the determination result is "YES", the microcomputer 18 determines that the magnetic tape 3 has been completely wound on either the supply reel 1 or the take-up reel 2. In step S3, the microcomputer 18 sends a control signal for stopping or reversing the rotation of a capstan motor (not shown) to stop or reverse the running of the magnetic tape 3 in FIG. Is output from the output terminal 13 at. At the same time, the microcomputer 8 outputs a signal for controlling various mechanical units in order to perform various operations accompanying the end of the winding of the magnetic tape 3, for example, taking out the cassette 100 and the like. In response to these control signals, the machine control unit 14 in FIG. 1 controls the operation of the related machine unit to realize the above-described operations.

However, if the determination result in the processing step S2 is “NO”, the microcomputer 8 determines that the magnetic tape 3 is
Also, it is determined that the light is not completely wound on any of the take-up reels 2 and the light input to the end sensor 5 or the start sensor 6 does not indicate that the reader portion has been detected. Then, the microcomputer 8 executes the processing step S1
Is repeated again.

In addition, in the processing step S1, even when it is determined that there is no light input to both the end sensor 5 and the start sensor 6, the microcomputer 8 performs the determination operation of the processing step S1 again. As described above, the determination operation of the microcomputer 8 is repeated until it is determined that the magnetic tape 3 has been completely wound on one of the supply reel 1 and the take-up reel 2 when the magnetic tape 3 is running. . Therefore,
Unless it is determined that the magnetic tape 3 has been completely wound on the supply reel 1 or the take-up reel 2, a control signal for stopping the running of the magnetic tape 3 is not output from the microcomputer 8 to the machine control unit 14 in FIG. .

The determination operation in the processing step S2 is actually performed as follows.

Actually, the microcomputer 8 receives not only the information input from the input terminals 9, 10 and 12, but also various other information related to the tape running system. One of them is a running speed of the magnetic tape 3 such as a standard running mode or a triple speed mode. Referring to FIG. 3, in microcomputer 8, this traveling speed information is stored in tape traveling position detecting section 81 of microcomputer 8.
In step (1), the running time of the magnetic tape is obtained by adding the remaining tape value information to the input terminal 12.

The tape running time is proportional to the length of the magnetic tape wound on the reel on which the magnetic tape is wound. Therefore, based on the obtained tape running time and the remaining tape value given to the input terminal 12, the leader portion at the end and the start of the magnetic tape 3 is determined by the supply reel 1 and the take-up reel 2.
, Or at a position where the supply reel 1 and the take-up reel 2 are not wound. The tape running position detecting unit 81 determines whether or not the leader portion at the end and the start of the magnetic tape 3 has run to the position facing the end sensor 5 or the start sensor 6 based on the known tape remaining value and the tape running time. It is determined by performing an operation. The comprehensive determination unit 80 operates according to the determination result.

The overall discriminating unit 80 detects the high potential applied to the input terminals 9 and 10 and constantly monitors the presence or absence of light input to the end sensor 5 and the start sensor 6. When there is a light input to the end sensor 5, the overall discriminating unit 80 determines that the discrimination result in the tape running position detecting unit 81 indicates that the leader portion at the end of the magnetic tape 3 has run to the position facing the end sensor 5. Confirm that it is shown. Only when it is confirmed that the end portion of the magnetic tape 3 has reached the position of the end sensor 5 in this manner, the comprehensive discriminating section 80
Determines that the running of the magnetic tape 3 is stopped (or reversed). Similarly, when there is a light input to the start sensor 6, the overall discriminating unit 80 determines that the tape running position discriminating unit 81 has determined that the leading portion of the magnetic tape 3 has run to the position facing the start sensor 6. Confirm that it indicates Only when it is confirmed that the winding start portion of the magnetic tape 3 has traveled to the position of the start sensor 6 in this way, the general determination section 80 determines to stop the traveling of the magnetic tape 3. The instruction unit 82 operates in response to the determination of the general determination unit 80.

The instruction unit 82 performs the processing of the processing step S3 shown in FIG. That is, when the overall discriminating unit 80 determines to stop the running of the magnetic tape 3 in response to the optical input to the end sensor 5, the command unit 82 causes the magnetic tape 3 to be completely wound on the winding reel 2 in FIG. (In the case of the figure). Similarly, in response to the light input to the start sensor 6, when the general determination unit 80 determines to stop the traveling of the magnetic tape 3,
The command unit 82 determines that the magnetic tape 3 has been completely wound on the supply reel 1 in FIG. 1 (in the case of FIG. 1). Then, the command section 82 outputs a signal for controlling the running of the magnetic tape 3. The control signal includes, for example, a signal for stopping the capstan motor (stopping the running of the magnetic tape 3) and a signal for reversing the rotating direction of the capstan motor (reversing the running direction of the magnetic tape 3) as described above. It is. However, if the overall discriminating unit 80 does not determine the stop of the running of the magnetic tape 3, the command unit 82 does not output any such control signal.

As described above, in the present embodiment, after the presence or absence of the optical input to the end sensor and the start sensor is detected, the optical input to the sensor is truly wound on the magnetic tape based on the separately detected remaining tape value. After confirming that the magnetic tape has been taken, the running of the magnetic tape is stopped or the running direction of the magnetic tape is reversed. Therefore, even when the magnetic tape has a scratched portion where the base film is exposed, and the detection output is obtained from the end sensor or the start sensor by a portion other than the reader portion, the microcomputer 8 controls the light input to these sensors. Is judged to be inappropriate. As a result, the running state of the magnetic tape is maintained as it is, so that there is no phenomenon that the running of the magnetic tape is stopped or reversed even though the magnetic tape is not completely wound as in the related art.

In the above embodiment, the case where the present invention is applied to an apparatus for recording / reproducing a video signal has been described.
The present invention is applicable to an apparatus for recording / reproducing an arbitrary signal.

[Effects of the Invention] As described above, according to the present invention, when the magnetic tape travels, the position of the transparent portion of the magnetic tape detected by the transparent portion detecting means that receives the transmitted light of the magnetic tape is determined at the time of the detection. By being confirmed by the remaining tape amount calculated by the remaining tape amount calculating means, both the detection output of the transparent portion detecting means that receives the transmitted light of the magnetic tape and the remaining tape amount calculated by the remaining tape amount calculating means are obtained. It is controlled based on. As a result, even when the transparent portion detecting means detects a portion other than the leader portion of the magnetic tape, for example, when the magnetic layer on the surface of the magnetic tape is scratched and the base film is exposed, the magnetic tape can be detected. Driving is controlled correctly. Therefore, the present invention can suppress the malfunction of the magnetic recording / reproducing device and improve the reliability of the device.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a tape running system of a video tape recorder according to one embodiment of the present invention. FIGS. 2 and 3 are flow charts for explaining the operation of the microcomputer shown in FIG. FIG. 4 is a schematic block diagram of a tape running system of the conventional video tape recorder. In the figure, 1 is a supply side reel, 2 is a take-up side reel, 3
Is a magnetic tape, 5 is an end sensor, 6 is a start sensor, 8 is a microcomputer, 9, 10, and 12 are input terminals of the microcomputer, 11 is a remaining amount calculation unit, 13 is an output terminal of the microcomputer, 14 is a machine control unit, 15 Is a detection output converter. In the drawings, the same reference numerals indicate the same or corresponding components.

Claims (1)

(57) [Claims] 1. A means for running a magnetic tape having a transparent portion, a means for optically detecting a transparent portion of a magnetic tape running by the running means, and a means for optically detecting the magnetic tape run by the running means. Means for calculating a physical quantity corresponding to the travel distance by a predetermined calculation; and a magnetic tape corresponding to the physical quantity calculated by the calculation means at the time of detecting the position of the transparent portion of the magnetic tape detected by the detection means. A magnetic recording / reproducing apparatus, comprising: means for controlling the running means based on the physical quantity calculated by the calculating means and the detection output of the detecting means by confirming the running distance of the running means.