JPS6034176B2 - Automatic tape attachment detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic tape loading detection device in a magnetic tape device using an automatic tape loading method, and particularly relates to an automatic tape loading detection device that detects when a magnetic tape is attached to another reel without using mechanical tape tension detection means. The present invention relates to an automatic tape mounting detection device that detects that a tape is automatically mounted on a tape.

As shown in Figure 1, files and
When loading the magnetic tape 3 from the reel 1 to the machine reel 2, an automatic tape loading system has recently been adopted in which the magnetic tape 3 is automatically loaded.

After the magnetic tape 3 is first installed in the state shown by the dotted line, the magnetic tape is suspended inside the columns 5 and 6 as shown by the solid line 3', and is run at a constant speed in a predetermined direction by the capstan 4, and the data is It is used for reading and writing. Therefore, it is necessary to automatically feed the magnetic tape 3 from the file reel 1 to the machine reel 2 and, after detecting that it is securely attached to the machine reel 2, to suspend the magnetic tape into the columns 5 and 6. be.

The following method is used to detect that a magnetic tape is attached to the machine reel 2.

At first, the speed of the machine reel 2 is set farther than the speed of the file IJ-route, and the magnetic tape 3 is automatically fed out as shown by the dotted line.

When the magnetic tape 3 is loaded onto the machine reel 2, the speed of the machine reel 2 is farther than the speed of the file reel 1, so the magnetic tape 3 is wound farther around the machine reel 2. Therefore, tension is applied to the magnetic tape 3. Therefore, the tension of the magnetic tape 3 is detected by an appropriate means to detect that it is attached to the machine reel 2. However, detection means such as micro switches and air flow control mechanisms are used to detect the tension of the magnetic tape, but such mechanical and physical means require the tension detection mechanism to be large. There wasn't.

Furthermore, Japanese Utility Model Publication No. 43-10986 describes that a rotary generator is installed on the tape winding shaft, and the winding of the tape around the winding shaft is detected by the change in the output of the rotary generator. Since this requires a special rotating generator, the detection mechanism must also become larger. Therefore, it is an object of the present invention to provide an automatic tape loading detection device which uses electronic means to detect whether a magnetic tape is reliably loaded onto a machine reel and which improves the above-mentioned problems. To this end, the tape tension detection method of the present invention includes a reel motor that drives a magnetic tape reel, a switching means that connects a power source to the reel motor, and an override reel motor connected to one input terminal. a comparison means to which a variable comparison reference voltage is applied to the other input terminal to which a voltage corresponding to the terminal voltage of is applied; a logic circuit to which the output of the comparison means is transmitted; It is equipped with a detection circuit for detecting the above specific state, and controls the switching means by the output of the logic circuit, and also monitors the terminal voltage of the reel motor to attach the magnetic tape. It is characterized by detecting that

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. FIG. 2 shows the circuit configuration of an embodiment of the present invention, and FIG. 3 shows its operational performance.

In the figure, 10' is a transistor, 11 is a file motor, 12 is a diode, 13 is a resistor, 14 is a capacitor,
15 is a comparison circuit, 16 and 17 are resistors, 18 is an MND circuit, and 19 is a detection circuit.

Transistor 10 functions as a switching means for connecting power supply voltage V to file moderator 111. The file motor 11 is a motor that drives the file reel 1 on which the magnetic tape 3 is wound, that is, a reel motor, and a diode 12 for suppressing surge voltage is connected to the file motor 1. . The terminal voltage of the capacitor 14 charged via the resistor 13 is applied to the first input terminal of the comparison circuit 15, and the second
A reference voltage Vref is applied to the input terminal via a resistor 16.

When a voltage of 10Vo is generated at the output terminal of the comparison circuit 15, the voltage of 10Vo is applied via the resistor IT, and as a result, the voltage at the second input terminal becomes Vref+ΔV. Further, when the -Vo voltage is generated at the output terminal of the comparison circuit 15, the -Vo voltage is applied via the resistor 17, and as a result, the voltage at the second input terminal becomes Vref-△
It becomes V. Therefore, the second input terminal voltage of this comparator circuit 15 is set to Vref plus ΔV and V by resistors 16 and 17.
It will be held at one of two voltages, ref-ΔV. In FIG. 2, since no control signal is applied to the control terminal of the AND circuit 18 at first,
The AND circuit 18 outputs a logic "0", the transistor 0 is in an off state, and the power supply voltage V is not applied to the file motor 11.

Therefore, the file motor 11 is stopped. At this time, the comparator circuit 15 outputs a voltage of 10Vo. Therefore,
Since this +Vo is divided by the resistors 17 and 16 and added to the reference voltage Vref, a voltage equal to Vref plus ΔV is applied to the second input terminal (reference voltage terminal) of the comparison circuit 16. Now, at time T in Fig. 3, AN
If a control signal is applied to the control terminal of the D circuit 18, the AN
D circuit 18 outputs logic "1".

This turns on transistor 10 and the file
The power supply voltage V is released to the motor 11, and the terminal voltage of the file motor 11 becomes as shown in FIG.
Motor 1 rotates. At the same time, since the capacitor 14 is charged via the resistor 13, the terminal voltage Vc of the capacitor 14 rises as shown in FIG. 3C. and time T2
When Vref reaches +ΔV, the comparator circuit 15 outputs -V.
Output o. As a result, the AND circuit 18 becomes logic "0"
is output, transistor 10 is turned off, and the file
The motor 11 is cut off from the power supply. However, the file 1 motor 11 continues to rotate by inertia and generates electricity, but the generated voltage gradually decreases, and the capacitor 1
The terminal voltage Vc of No. 4 also decreases. On the other hand, as mentioned above, time
2, when the output voltage of the comparator circuit 15 becomes -Vo,
This time, this one Vo is divided between the resistors 17 and 16, and the voltage at the second input terminal of the comparator circuit 15 has decreased to Vref-ΔV. Then, at time T3, when the terminal voltage of the capacitor 14 reaches this Vref-△V, the comparator circuit 15
outputs 10Vo again, so AND circuit 18 is logical
1” is output, transistor 0 becomes conductive, and the file
A power supply voltage V is applied to the motor 11 . And Tokio Junior High School 4
At , transistor 10 is turned off again. Therefore, due to the rotation of the file motor 1, the magnetic tape 3 sent out from the file reel 1 is transferred to the machine reel 2.
This process is repeated until it is installed.

However, when the magnetic tape 3 is loaded onto the machine reel 2 at time K in FIG. 3, the speed of the machine reel 2 is faster than the speed of the file reel as described above.
The magnetic tape 3 is now under tension and the file motor 1 is now rotated at a faster speed than before.

Thus, based on the voltage generated by the file motor 1, the terminal voltage of the capacitor 14 increases as shown in curve A shown in FIG. 3C, and does not match the Vref-ΔV voltage. Therefore, the logic "1" for turning on the transistor 10 is no longer output from the AND circuit 18. Therefore, while the magnetic tape is not attached to machine reel 2,
AND circuit 1 for each time L-~=To in FIG.
The logic "1" that was generated from 8 can no longer be obtained.

Therefore, the detection circuit 19 detects whether or not a logic "1" is generated from the AND circuit 18 during a time exceeding a certain period of time To.
By detecting this, that is, by detecting that the magnetic tape remains in a specific state for a certain period of time or more, it is possible to reliably detect that the magnetic tape is mounted on the machine reel. As explained above, according to the present invention, based on monitoring the terminal voltage of the reel motor, it is possible to determine whether tension is applied to the magnetic tape by electronic means, in other words, whether the magnetic tape is attached to the machine reel. can be reliably detected.

Furthermore, since the motor is driven in pulses and the motor induced voltage is detected while the applied pulses are at rest, the effect of fluctuations in the motor winding resistance can be eliminated and accurate rotational speed detection is possible. Since the motor itself is driven by an on/off switching method, it can also be applied to high-output motor drive circuits. Therefore, it is possible to accurately detect that a magnetic tape is mounted on a machine reel without using conventional mechanical detection methods, and it is possible to downsize the magnetic tape device.

[Brief explanation of the drawing]

FIG. 1 is a simple explanatory diagram of a magnetic tape device, FIG. 2 is an explanatory diagram of a circuit configuration of an embodiment of the present invention, and FIG. 3 is an explanatory diagram of its operating state. In the figure, 1 is a file/reel, 2 is a machine/IJ-role,
3 is a magnetic tape, 4 is a capstan, 5 and 6 are columns,
10 is a transistor, 11 is a file motor, 12 is a diode, 13 is a resistor, 14 is a capacitor, 15 is a comparison circuit, 16 and 17 are resistors, 1 and 8 are AND circuits, 1
9 indicates a detection circuit, respectively. O figure, two-legged spear, three females

Claims (1)

[Claims] 1. A reel motor that drives a magnetic tape reel;
switching means for connecting a power source to the reel motor; and comparison means for applying a voltage corresponding to the terminal voltage of the reel motor to one input terminal and applying a variable comparison reference voltage to the other input terminal. and a logic circuit to which the output of the comparison means is transmitted, and a detection circuit for detecting that the output of the logic circuit is in a specific state for a certain period of time or more, and controlling the switching means by the output of the logic circuit. , an automatic tape loading detection device which detects loading of a magnetic tape by monitoring the terminal voltage of the reel motor.