JPS6348089B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a tape feeding device, and particularly in a tape feeding device that performs rapid start-stop operations, it is possible to feed a tape at a constant speed while maintaining a constant tension. It relates to a device suitable for transferring from one reel to another.

[Prior art]

As a conventional magnetic tape device, IBM Technical
Disclosure Bulletin Vol 21.No.7December 1978
p2692～2693 “Storage−Buffered Rotary
Actuating Tape Drive”.

This tape feeding method is called a reel to reel method, in which two reels directly take charge of the tape feeding function. In this type of tape feeding, the tape is fed on two reels, but the amount of tape winding on the two reels is not the same, and when performing rapid starts and stops, there is a dynamic response between the two reels. There will be a difference. The difference in tape feed amount caused by this is
This is absorbed by a rotating tape buffer mechanism. This mechanical buffer prevents the two reels from interfering with each other, allowing them to be driven independently. On the other hand, the tape tension is adjusted by a tension arm. This type of magnetic tape device requires a complicated tape feeding mechanism, making the system expensive. Further, in the case of adjusting the tape tension using the tension arm method, there is a drawback that precise adjustment cannot be performed because the tape tension increases or decreases depending on the position of the tension arm.

Next, regarding the performance of rapid start-stop, conventional systems are slower than air buffer systems that apply vacuum pressure and cannot perform rapid start-stop. One of the reasons for this is that in the tension arm system, the tension arm is generally supported by a spring.
When the tension arm moves, the length of this spring changes, and the principle of generating tape tension by the spring force is applied. Therefore, mechanical resonance occurs between the movable mass of the tension arm and the spring. As a result, there is a limit to the frequency that the tension arm method can respond to, and in reality it is as low as several tens of Hz.

Another reason is that the structure of the mechanism including the tape buffer and tension arm is complex, resulting in a large number of mechanical parts that move together with the tape, reducing the rigidity of the tape running section, and lower the resonance point. In such a situation, there is a problem in that a high-speed start/stop cannot be expected.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a tape feeding device equipped with a tape buffer mechanism that is small in size and has a simple configuration to enable high-speed start-stop operations of the tape.

[Summary of the invention]

The present invention is a mechanical tape feeding device that is compact, lightweight, and inexpensive, and is equipped with a buffer mechanism that can directly apply tape tension and that makes the tape tension uniform over a certain area. It is.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a magnetic tape device equipped with an embodiment of the device of the present invention. In this figure, a reel-to-reel type magnetic tape device in which reels 1 and 2 perform direct operation is shown. The Reel method was selected as an example because it has a greater effect of making the tape feeding device smaller and cheaper than the conventional method, and is not the essence of the present invention.

A constant tape tension is applied to the tape 8 discharged from the supply reel 1 by a high speed actuator type tape buffer 20. In the figure, the section indicated by distance l is the tape buffer section. The tape tension in this section is uniform. An example of the configuration of the high-speed actuator type tape buffer 20 is shown in FIG. 2, and the details will be described later. After passing through the high-speed actuator type tape buffer 20, the tape 8 passes through a data conversion block consisting of tape guides 11a, 11b and a magnetic head 3, and is wound onto a take-up reel 2 via a tachometer 9. Here, in the tachometer 9, an idler idler rotates due to frictional force with the tape 8, and an encoder that generates N pulses per rotation is incorporated in the lower part of the idler.

Next, the tape feeding operation will be explained.

The supply reel 1 and the take-up reel 2 each have a built-in motor. These motors are controlled by a reel drive block (not shown) so that the circumferential speed of the outermost periphery of the two reels containing the tape is at a predetermined speed. At this time, the actual tape speed is detected from the output pulse of the tachometer 9. If the tape speed indicated by the tachometer 9 deviates to the high speed side compared to the target tape speed in the reel drive block, a deceleration operation signal is applied to the reel motor. In the opposite case, an operation signal to increase the speed is applied.

The tape winding amount on the two reels 1 and 2 is
Depends on the distance from the edge of the tape. As a result,
The moments of inertia that affect the dynamic characteristics of the two reels 1 and 2 are different, and this effect appears on the tape speed, tape feed amount, etc. This phenomenon is particularly noticeable during start-stop acceleration and deceleration. Its magnitude increases in proportion to the acceleration of the start stop. The difference that appears in the dynamic characteristics of both reels actually appears as a difference in tape feed amount,
This causes the tape length between the two reels 1 and 2 to change. When the length of the tape between the reels becomes longer than the original length, the tape loosens and the tape tension decreases by the lengthened length. On the other hand, if the length is too short, the tape tension will increase. If the dynamic characteristics of the two reels are appropriately compensated for, it is expected that the tape tension fluctuations due to the above-mentioned causes will be reduced. Alternatively, it creates extra power that enables even faster start-stops.

However, it is not possible to reduce tape tension fluctuation to zero, and in order to bring it close to zero, it is necessary to compensate for extremely precise dynamic characteristics, including compensation for nonlinear factors such as the frictional force generated in the tape running device. The need arises and great effort is required. Therefore, these become factors that increase the product cost of the reel drive system. In order to achieve a system that is balanced in terms of equipment cost, other measures are needed to adjust for tape tension fluctuations.

The high-speed actuator type tape buffer 20 described above can cope with such a situation. In the buffer section 1, the structure is such that it can move very smoothly. When the tape tension increases due to the above-mentioned reasons and strikes against a constant tension acting on the buffer 20, the buffer 20 is pulled by the tape and moves to a balanced position in balance with the tape tension. As the buffer 20 moves, the tape loosens by that distance and the tape tension decreases until it moves to a point where it balances the constant tension acting on the buffer 20. This can be similarly explained when the tape tension decreases by simply reversing the direction of buffer movement.

In this manner, the high speed actuator buffer 20 automatically adjusts tape tension. Furthermore, the smaller the frictional force of the buffer 20, the better the accuracy can be obtained. Next, the frequency band that can respond to tape tension fluctuations can be determined from the increased response acceleration determined by the tape tension acting on the buffer 20 and the mass of the movable part. Therefore, it is desirable that the mass of the movable part be lightweight.

There is an error in the amount of tape feed between the two reels 1 and 2, and if it accumulates, it will deviate from the buffer section l of the high-speed actuator type buffer 20. The buffer 20 has a sensor that detects the position of the buffer 20, and normally the tape length between the two reels is managed so that the buffer 20 operates at the center of the buffer section l. That is, when the position of the buffer 20 moves to the side where the tape length between the two reels is shorter, an operation signal is issued to the supply reel drive block to correct the tape amount on the supply reel 1. This operation is similarly corrected when the buffer 20 moves toward the side where the tape length between the two reels becomes longer.

The aforementioned high-speed actuator type buffer 20
The configuration of is explained below.

FIG. 2 shows an example of this, in which a voice coil type motor is applied to the actuator motor 23. The tape 8 is rotatably supported by the idler 7a. This idler 7a is attached to a carriage guided by a support rail 21 so that it can move smoothly in a linear direction. The carriage 22 is an actuator motor 23
is directly connected to. The carriage 22 includes a sensor 4 for detecting a positional error with respect to the support rail 21.
0 is included. Although the principle of detecting the position of the sensor 40 is not essential to the present invention, a non-contact sensor that does not impose a load on the movement of the buffer 20 is desirable. Furthermore, in order to correct the tape length between two reels, not only the position signal but also the speed signal may be effective. Therefore, the sensor 40
can be arbitrarily selected depending on the control method for tape length correction.

In order to apply a constant tape tension to the tape 8, a constant current is supplied to the actuator motor 23 from a power supply circuit 24. In the case of the actuator motor 23, within the movable stroke,
It has been technically confirmed that a force proportional to the applied current can be uniformly generated. In the case shown in FIG. 2, the force of the actuator motor 23 acts in the direction of the arrow in the figure, and acts on the tape tension of the tape 8 via the idler 7a.

Figure 3 shows another example of buffer 20.
This is an example in which a DC motor configured to transmit rotational torque through a pulley 31 is applied to the actuator motor 32. A DC motor is preferable as the actuator motor 32 because of its large starting torque.
In the present invention, there are no restrictions on the configuration or principle of the actuator motor 32 as long as it can generate rotational torque. In FIG. 3, a steel wire 30 is wound between rotary pulleys 31 and 33. This wire 30 is coupled to the carriage 22. As a result, the rotational torque of the rotary pulley 31 is transferred to the carriage 22 by the steel wire 30.
is propagated as a force in a straight line. Rotating pulley 3
3 is configured to be movable, and a rotary pulley 3
In order to properly transmit the rotational torque of 1 to the carriage 22, the tension of the steel wire can be adjusted. In order to apply a constant force to the idler 7a, the current applied to the actuator motor 32 is supplied from the power supply circuit 24. It has been confirmed that, in the case of a DC motor, the rotational torque generated by the actuator motor 32 is proportional to the applied current, regardless of the rotational position. For this purpose, the power supply circuit 24 has a current control function that allows a constant current to flow through the actuator motor 32.

FIG. 4 shows yet another example of the buffer 20, which is characterized in that a swing arm type actuator motor is applied to the actuator motor 50. An arm 51 that fixes the rotatable idler 7a also serves as an armature of the actuator motor 50. Therefore, the rotational torque generated by the actuator motor 50 is transmitted to the idler 7a around the support body 52 configured to freely rotate. It has been confirmed that the rotational torque generated in the actuator motor 50 is also proportional to the motor current.

With the above configuration, tension can be directly applied to the tape by the freely rotatable idler, and the applied tension can be made uniform over the buffer section. As a result, precise tension adjustment is possible, and the conventional system consisting of a tension arm and a tape buffer can now be adjusted into one.
As a result, the mass of the moving parts in the tape feeding device can be significantly reduced, and the running system including the tape can be By increasing the rigidity, the tape resonance point rises and higher speeds can be achieved. In addition, with regard to this, it is possible to eliminate the mechanical resonance of the tension arm that occurs due to the fact that conventional tension arm method tension adjustment uses a spring to generate tension, making it possible to increase speed. Become.

〔Effect of the invention〕

As described above, according to the present invention, the structure is simple and compact, and the tape can be started and stopped at high speed, thereby increasing the speed.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a magnetic tape device equipped with an embodiment of the present invention, and FIGS. 2 to 4 are diagrams showing the detailed configuration of an embodiment of a high-speed actuator type buffer used in the present invention. be. 1... Supply reel, 2... Take-up reel, 3...
Magnetic head, 8... tape, 9... tachometer,
11a, 11b... Tape guide, 20... High speed actuator type tape buffer, 21... Support rail, 22... Carriage, 23... Actuator motor, 24... Power supply circuit, 30... Steel wire, 31... Rotating pulley, 33... Free rotation pulley, 32... Actuator motor,
40... Tape buffer position detection sensor, 50...
...actuator motor, 51...armature arm, 52...support body.

Claims (1)

[Scope of Claims] 1. A magnetic tape is transported from the supply reel through a read/write head disposed between the reels to the take-up reel by driving the supply reel and the take-up reel by separate motors, respectively. , a magnetic tape device that reads and writes information by this transfer, and includes a reel drive means that drives the reel via the motor in response to a predetermined target signal, and a reel drive means that is located between the reels and controls the tape length between the reels. In an actuator buffer type tape feeding device having adjustment means, the means for adjusting the tape length between the reels is an idler that rotatably supports the magnetic tape;
It consists of a support mechanism that supports the idler so that it can reciprocate linearly, and an exchanger that is directly connected to the support mechanism and generates a force that moves the support mechanism when supplied with a predetermined target current. Additionally, a tape buffer position detection sensor is provided for detecting the linear reciprocating position of the idler, and the output of the sensor is used to control the reel driving means so that the operating position is within a predetermined range. Actuator buffer type tape feeding device.