JPS60136051A - Magnetic tape device - Google Patents

Abstract

PURPOSE:To reduce the length of a tape buffer mechanism part by using a means which changes a tape loop stabilizing point in response to the tape drive mode. CONSTITUTION:A tape driving direction detecting circuit 11 decides the driving direction of a tape by means of a double phase tachometer 10 and informs the decided direction to a tape control stabilizing point shift circuit 15. While a tape feed speed detecting part 12 sends the tachopulse interval to a stabilizing point shift clock generating circuit 13. The circuit 13 sends a stabilizing point shift clock to the circuit 15 every time the tachopulse interval becomes less than the prescribed value. The circuit 15 decides the moving direction of the stabilizing point from the information of the circuit 11 and shifts the stabilizing point every bit by the input given from the circuit 13. While the tape position information is loaded to a tape control operator 16 and processed by the loading signal of a dividing circuit 14. Then a tape is positioned at the stabilizing point via a motor drive circuit 17. Thus the stabilizing point is set at points X0, X1 and X' in the stop, FWD and emergent damping modes respectively. Then the stabilizing point is set at a point X2 in a BKWD mode. Thus the length of a tape buffer mechanism part can be reduced down to about half compared with the conventional value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetic tape device, and more particularly to a magnetic tape device in which a tape loose control stable point in a tape buffer mechanism can be switched.

[Background of the invention]

Generally, magnetic tape devices are equipped with a tape loosening mechanism to protect the tape during emergency braking. in this case,
The length of the tape buffer mechanism is determined by the amount of tape movement during emergency braking.However, tape position control is performed so that the tape loose position within the buffer mechanism is always at a constant point, that is, the tape control stable point. It controls the motor. However, in conventional magnetic tape devices,
The tape control stable point is fixed for any operating mode, and is usually located at a central point within the tape buffer mechanism 4, as shown in FIG. Therefore, in case of sudden braking when driving in the forward direction, the tape loop P moves by -L from the stable point X, and when driving in the reverse direction, the tape loop P moves by +L from the stable point X. 4, it was necessary to ensure a length of at least 2L, making it difficult to miniaturize the device.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and provide a magnetic tape device that can significantly shorten the length of the tape buffer mechanism.

[Summary of the invention]

In order to achieve the above object, the present invention includes a tape buffer mechanism between a capstan roller and a tape reel, and rotates the tape reel in accordance with the output of a tape loop position detection means provided in the tape buffer mechanism. In the magnetic tape device, the tape loop is positioned at a predetermined stable point within the tape buffer mechanism by controlling the tape loop stability according to the running mode of the tape.

The present invention is characterized in that a means for changing the fixed point is provided.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a front view of a magnetic tape device showing an embodiment of the present invention, in which 1 is a capstan, 2 is a file reel, and 3 is a front view of a magnetic tape device showing an embodiment of the present invention.
is a machine reel, and tape buffer mechanisms 4a and 4b are provided between sb, i, 2.1 and 6, respectively, and multiple tape buffer mechanisms are provided within each tape buffer mechanism.

In the 9-tape buffer mechanism in which several vacuum switches 5 are arranged, the tape always maintains a constant tension due to the vacuum suction force from the terminal end, and the vacuum Since the switch group 4 is divided into two groups, the vacuum side and the atmospheric pressure side, these switch 5
The tape loop position can be identified by the ON-OFF state of .

FIG. 3 is a block diagram showing a circuit system for switching the tape control stable point in the magnetic tape device, and only the portion on the file reel 2 side is shown here. In the figure, 1o is a two-phase tachometer that outputs pulses in conjunction with the capstan 1, 11 is a running direction detection circuit, 12 is a tape feed speed detection circuit, 13 is a stable point movement clock generation circuit, 14 is a frequency dividing circuit, 15 is a control stable point moving circuit; 16
17 is a motor drive circuit; 18 is a motor for driving the file reel 2;

In the above configuration, the capstan 1 is moved in the forward direction (F'WD direction) or reverse direction (BK
(WD direction). The running direction detection circuit 11 includes a two-phase tachometer 10 mounted coaxially on the cab's tongue.
It is determined whether the drive is FWD running or BKWD running, and this is notified to the tape control stable point moving circuit 15 which is constituted by a shift register. On the other hand, the tape feed speed detection section 12 measures the tacho pulse interval from the tachometer 10 and sends it to the stable point movement clock generation circuit 16. The circuit 13 counts the tacho pulse interval using a reference clock, and when the count value becomes less than a predetermined value (the speed becomes more than the specified speed) 1
Stable point moving circuit 1 with tape control stable point moving clock at each time
Send on 5th. The tape control stable point moving circuit 15 determines which direction to move the tape control stable point up or down based on the information from the running direction detection circuit 11, and stabilizes the tape by inputting the movement clock from the stable point moving clock generation circuit 13. Move the points one bit at a time. That is, the tape position information is shifted one bit at a time.

In addition, by the load signal sent from the frequency dividing circuit 14,
The tape position information shifted by the tape control stable point moving circuit 15 is loaded into the tape control computing unit 16, and after predetermined processing is performed, the tape is positioned at the tape control stable point via the motor drive circuit 17. The reel motor 18 is driven.

According to the present invention, the control stable point X when the tape is stopped.

is at the position shown in Fig. 4(a), but during FWD driving, the final tape control stability point is position Xl shown by the solid line in Fig. 4(b), and during emergency braking, the tape position is at the position shown by the dotted line. Move to X'. In addition, when driving in BKWD, this is the opposite, and as shown in Fig. 4 (c), the control stable point is X,
becomes. Therefore, according to the present invention, the length of the tape buffer mechanism, which conventionally required at least 2L, can be shortened to approximately half the length, and the size of the device can be significantly reduced.

In the embodiment, a vacuum switch is used as the tape detection mechanism, but this may be replaced with an optical sensor, a capacitive sensor, or the like. Further, the function of the tape control stable point moving circuit 150 may be performed in the tape control arithmetic unit (microprocessor) 16. Also,
The timing of movement of the tape control stable point does not necessarily depend on the tape feeding speed of the capstan. The amount of movement of the tape control stable point also does not need to be constant, and may be changed depending on conditions such as various operation modes and the amount of tape wound on the reel.

〔Effect of the invention〕

As described above, according to the present invention, since the tape control stable point is moved depending on the operation mode, the length of the tape buffer mechanism can be shortened, and the apparatus can be made smaller.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining tape position movement in a tape buffer mechanism section, FIG. 2 is a front view of a magnetic tape device showing an embodiment of the present invention, and FIG. 3 is a diagram showing an embodiment of a tape control system. The block diagram and FIGS. 4(a) to 4(c) are diagrams for explaining tape position movement in the apparatus of the present invention. 1 Capstan, 2... File reel, 3 Mann reel, 4 (4a, 4b) Tape buffer mechanism, 5 Vacuum switch, 11. Running direction detection unit, 15. Tape control stable point movement circuit, 12. Tape feed speed detection. Circuit, 16. Stable point movement clock generation circuit, 14. Frequency dividing circuit, 16.. Tape control arithmetic unit, 17.
Motor drive circuit. Representative Patent Attorney Akio Takahashi 1rEJ Figure 2 6 Figure 4 31!5

Claims (1)

[Claims] A tape buffer mechanism is provided between the capstan row 2, the tape, and the reel, and the rotation of the tape reel is controlled according to the output of a tape loop position detecting means provided in the tape buffer mechanism, and the tape loop is moved between the tape and the tape. What is claimed is: 1. A magnetic tape device configured to align the tape loop at a predetermined stable point within a buffer mechanism, further comprising means for changing the tape loop stable point in accordance with the running mode of the tape.