JPH06259851A - Tape loading device - Google Patents

Abstract

PURPOSE:To prevent tape tension from varying even when tape drawing speed is suddenly accelerated and decelerated at the time of loading. CONSTITUTION:A rotational frequency of a loading motor 6 and loading positional information are inputted to a loading speed detector 17, where the tape drawing speed V at the loading time is obtained, and its acceleration Vacc is obtained via a differentiation calculator 19. On the other hand, a radius Rt and inertia Jt of a take-up reel are detected by blocks (reel radius detector and reel inertia detecor) 20 and 21, and the information of the Vacc, Rt and Jt is inputted to a loading acceleration compensating torque calculator 23, where correcting torque for suppressing a tension variation attending upon a tape speed change at the loading time is calculated. Torque obtained by adding torque proportional to the reel radius and the compensating torque is imparted to the take-up reel at the loading time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape loading device used in a rotary head type recording / reproducing device such as a video tape recorder.

[0002]

2. Description of the Related Art In recent years, video tape recorders (VT
R) mainly uses a cassette tape, and has a tape loading device for pulling out the tape from the cassette and winding the tape around a drum having a rotary head mounted when used.

An example of a conventional tape loading device is disclosed in, for example, JP-A-63-224063.

2 and 3 are views for explaining the loading operation of the above-described conventional tape loading device, FIG. 2 shows a loading start state, and FIG. 3 shows a loading completion state.

2 and 3, 1 is a cassette,
2 is a loading ring, 3 to 5 are posts, 6 is a loading motor, 7 is a worm gear, 8 is a tape, 9 is a drum, 10 is a pinch roller, 11 is a capstan, 12
Is a supply side reel, and 13 is a winding side reel.

The operation of the conventional tape loading device shown in FIGS. 2 and 3 will be described below.

When the cassette 1 is mounted on the VTR, the loading posts 3, 4 and 5 provided on the loading ring 2 are inserted into the tape pull-out position shown in FIG. 2 as shown in FIG.

When the worm gear 7 is driven by the loading motor 6, the loading ring 2 rotates in the direction of the arrow to pull out the tape 8, and the tape is wound around the drum 9 as shown in FIG. The operation is completed.

During the loading operation, the supply reel 12 of the cassette 1 is braked, while the take-up reel 13 is opposed to the tape pull-out direction.
A constant torque is applied.

Conventionally, the loading ring 2 is rotated at a substantially constant speed from the state shown in FIG. 2 to pull out the tape from the take-up reel 13 and pull it to the position shown in FIG.

[0011]

In recent years, the VTR has been recorded for a longer time, and the thinning of the tape and the upsizing of the cassette have been spurred on. There is also a demand for shortening the time from inserting the cassette to running the tape, that is, increasing the loading speed.

As the cassette becomes larger, the inertia of the reel increases, and when the loading speed becomes faster, the tape pulling speed also changes rapidly. Therefore, even if the torque applied to the take-up reel 13 is constant. , The change in tension applied to the tape becomes very large, which may result in damage to the tape, or the tape may fall off the loading post and cause the tape to break.

In particular, as the tape becomes thinner, the tape damage due to the fluctuation of tension at the time of loading becomes more and more a serious problem.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a tape loading device in which fluctuations in tape tension are reduced even when tape loading is speeded up.

[0015]

To achieve the above object, a tape loading apparatus of the present invention comprises a tape pulling speed detecting means for detecting tape pulling speed information,
Differentiating means for calculating tape pull-out acceleration information, reel winding diameter detecting means for detecting reel winding diameter information, reel inertia detecting means for detecting reel inertia information, and correction torque information for suppressing tape tension fluctuations are provided. And a correction torque calculating means for calculating.

[0016]

According to the present invention, with the above-described structure, the correction torque information is calculated from the tape pull-out acceleration information, the reel winding diameter information, and the reel inertia information, and the reel is driven by the torque according to the calculated value. It is intended to suppress the fluctuation of tension.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the principle of the present invention will be described before describing the embodiments of the present invention.

When the tape tension is T, the radius of the take-up reel is Rt, the inertia of the take-up reel is Jt, the tape pull-out speed acceleration at the time of loading is Vacc, and the take-up reel torque is Qt. It holds.

Qt = Rt.multidot.T + (Jt / Rt) .Vacc (Formula 1) The second term on the right side of Formula 1 is a torque fluctuation component due to the acceleration of the tape pulled out at the time of loading, By performing torque compensation on the side reel torque Qt for canceling this fluctuation component, it is possible to configure a control system with less tape tension fluctuation.

FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, 1 to 13 are the same constituent parts as those denoted by the same reference numerals in FIGS. 2 and 3, and 14 is a frequency generator for detecting the number of rotations of the loading motor 6.
5 is a waveform shaper that shapes the output signal of the frequency generator, 16 is a counter that counts the output signal of the waveform shaper 15, and 17 is the output signal of the waveform shaper 15 and the counter 1.
A loading speed detector for detecting the tape withdrawing speed from the output signal of 6, a reset terminal 18 for supplying a reset signal to the counter 16, a differential calculator 19 for differentiating the output signal of the loading speed detector 17, and a winding device 20. Reel radius detector for detecting the winding diameter of the take-up reel 13, 2
1 is a reel inertia detector that detects the inertia of the reel from the output signal of the reel radius detector 20 and the cassette information,
Reference numeral 22 is a reel radius proportional torque calculator that calculates a torque corresponding to the first term on the right side of Expression 1 from the output signal of the reel radius detector 20, and 23 is an output signal of the differential calculator 19 and an output signal of the reel radius detector 20. And reel inertia detector 2
A loading acceleration compensating torque calculator for calculating a torque corresponding to the second term on the right side of the equation 1 from the output signal of 1;
4 is an adder for adding the output signal of the reel radius proportional torque calculator 22 and the output signal of the loading acceleration compensation torque calculator 23, and 25 is a reel drive for driving the take-up reel 13 according to the output signal of the adder 24. Circuit.

In the tape loading apparatus of this embodiment, the supply reel 12 is braked during loading, and the tape is pulled out from the take-up reel 13 as in the conventional example.

At this time, the frequency signal FGL is generated from the frequency generator 14 generated according to the rotation of the loading motor 6.
Is obtained. This corresponds to the rotation speed of the loading ring 2, and the counter 1 is passed through the waveform shaper 15.
6 and the loading speed detector 17.

The counter 16 is supplied with a reset signal from the reset terminal 18 at the loading start position so that the position information LP from the loading start can be detected. At the start of loading, the reset terminal 18
When a reset signal is supplied to the counter 16 from the counter 16, the count value of the counter 16 is cleared, and thereafter, the count value is incremented each time a pulse is supplied from the waveform shaper 15. By operating the counter 16 in this way, the output information LP of the counter 16 indicates the loading position information from the start of loading.

The loading speed detector 17 is supplied with the loading position information LP and the frequency signal FGL, and the tape pulling speed V at the time of loading is detected from these information. The tape pull-out speed V is different from the rotation speed of the loading ring, but if the positional information of the loading ring and the rotation speed information of the loading ring are known, the tape pull-out speed is calculated from the loading path using a conversion formula or a calculation table prepared in advance. The speed V can be obtained.

The tape withdrawing speed can also be derived by using the winding diameter information of the take-up reel and the angular velocity information. However, if the tape falls off the loading post or is cut during loading,
The tape withdrawal speed that is ejected changes abruptly, and controlling the take-up reel torque based on this erroneous tape withdrawal speed may cause the tape to drop out of the loading post or cause tape breakage. In this embodiment, a method of deriving the tape pulling speed from the position information of the loading ring and the rotation speed information of the loading ring is adopted.

The tape acceleration Vacc at the time of loading can be obtained from the tape pull-out speed signal V via the differential calculator 19.

The reel radius detector 20 detects the reel diameter information Rt on the take-up reel from the frequency signal generated in accordance with the rotation of the take-up reel. (For example, a method of detecting the reel rotation amount when the tape is pulled out by a certain amount is often used.) In the reel inertia detector 21, the reel winding diameter information Rt, the tape thickness of the cassette, the hub diameter, and the cassette size. The cassette information such as is input, and the reel inertia Jt is output from these information.

The reel radius proportional torque calculator 22 is for calculating the first term on the right side of the mathematical expression 1, and calculates the product of the set tape tension T at the time of loading and the reel radius Rt, and the result is added by the adder 24. Output to.

Loading acceleration compensation torque calculator 23
The reel radius information Rt and the reel inertia information Jt.
, The tape acceleration Vacc at the time of loading is input, and the second term on the right side of Expression 1 is calculated.

The adder 24 calculates the sum of the torque information proportional to the take-up reel radius and the loading acceleration compensating torque information, and outputs the result to the reel drive circuit 25. The described torque Qt is applied.

As described above, in this embodiment, it is possible to detect the tape acceleration, the reel radius, and the reel inertia at the time of loading, and to reduce the fluctuation of the tape tension even if the tape speed at the time of loading suddenly changes. Therefore, tape damage such as cutting or dropping of the tape can be prevented. Therefore, the loading time can be shortened, and it is very effective for increasing the size of the cassette and thinning the tape.

In this embodiment, the tape is pulled out from the take-up reel during the loading operation, but the tape may be pulled out from the supply reel.

Further, although the microcomputer is widely applied to electronic equipment because it can easily perform various calculations, the block 26 surrounded by a dotted line in FIG. 1 is constituted by a microcomputer, and each calculation described above is executed by software. You may go with clothing.

[0034]

As described above, according to the present invention, the correction torque for suppressing the fluctuation of the tape tension is calculated and the reel is driven based on the calculated correction torque, so that the tape is less damaged even if the loading speed is increased. A tape loading device can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram of a tape loading device according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a loading operation of a conventional tape loading device.

FIG. 3 is a diagram for explaining a loading operation of a conventional tape loading device.

[Explanation of symbols]

 1 cassette 2 loading ring 3 post 4 post 5 post 6 loading motor 7 worm gear 8 tape 9 drum 10 pinch roller 11 capstan 12 supply side reel 13 winding side reel 14 frequency generator 15 waveform shaper 16 counter 17 loading speed detector 18 reset terminal 19 differential calculator 20 reel radius detector 21 reel inertia detector 22 reel radius proportional torque calculator 23 loading acceleration compensation torque calculator 24 adder 25 reel drive circuit

Claims (7)

[Claims] 1. With the rotation of the loading ring, a tape provided on the loading ring is used to pull out the tape from either the reel on the winding side of the cassette or the reel on the supply side, and the tape is wound around the tape guide drum. A tape loading device, wherein tape pull-out speed detecting means for detecting tape pull-out speed information corresponding to the tape pull-out speed and output signal of the tape pull-out speed detecting means are differentiated to correspond to the tape pull-out acceleration. Differentiating means for calculating the tape pull-out acceleration information, a reel frequency generator for generating a reel frequency signal corresponding to the rotation speed of the reel on the side from which the tape is pulled out, and the reel frequency generator based on the output signal of the reel frequency generator. Reel reel diameter detection hand that detects reel reel diameter information corresponding to reel reel diameter A reel inertia detecting means for obtaining reel inertia information corresponding to the inertia of the reel from an output signal of the reel winding diameter detecting means, an output signal of the differentiating means, an output signal of the reel winding diameter detecting means, and the reel inertia. Comprising correction torque calculation means for calculating correction torque information for suppressing fluctuations in the tension of the tape from an output signal of the detection means, and a reel drive circuit for receiving the output signal of the correction torque calculation means and driving the reel. Tape loading device. 2. The tape pulling speed detecting means in claim 1 integrates a loading ring frequency generator for generating a loading ring frequency signal corresponding to the rotation speed of the loading ring and an output signal of the loading ring frequency generator. Means for calculating loading ring position information corresponding to the rotational position of the loading ring, and tape pull-out speed information using a predetermined summing means from the output signal of the loading ring frequency generator and the output signal of the integrating means. A tape loading device, comprising: a tape withdrawing speed calculating means for calculating 3. The tape loading device according to claim 2, wherein the accumulating means has a reset means for setting the accumulating means to a predetermined value when the loading ring reaches a predetermined position. 4. The predetermined summing means according to claim 2, wherein the predetermined summing means is a conversion formula for associating the loading ring frequency signal, the loading ring position information and the tape withdrawing speed information. Tape loading device. 5. The predetermined summing means according to claim 2, wherein the predetermined summing means is a conversion table that correlates the loading ring frequency signal, the loading ring position information, and the tape pulling speed information. Tape loading device. 6. The tape loading device according to claim 1, wherein the tape withdrawing speed detecting means calculates tape withdrawing speed information from the output signal of the reel frequency generator and the output signal of the reel winding diameter detecting means. 7. The correction torque calculating means according to claim 1, which is proportional to the tape pull-out acceleration information and the reel inertia information and inversely proportional to the reel winding diameter information, is output as the correction torque information. The tape loading device characterized in that