JP2002197755A - Magnetic recording/reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine a tape area by only one reel detector, and to perform appropriate deceleration processing. SOLUTION: A reel area is calculated by determining a reel radius from the quantity of tape feeds detected by the rotation detector and the number of rotations of a reel detected by the reel detector when a tape is driven at a constant speed. A deceleration point is set on the basis of the reel area. After a rapid feed is suspended, the tape is driven at the constant speed, and the reel radius is determined. A real tape thickness is calculated from the difference between the calculated reel radius and the initially set reel radius. A subsequent deceleration point is changed on the basis of the real tape thickness to reset the run conditions of the tape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus such as a video tape recorder, and more particularly to a magnetic recording / reproducing apparatus capable of high-speed running in fast forward or rewind.

[0002]

2. Description of the Related Art Generally, in a video tape recorder,
When a tape is fed at high speed, such as fast forward (FF) or rewind (REW), the tape speed is reduced when approaching the end of the tape to protect the tape.
The deceleration point at this time is set based on the reel area of the take-up reel or the supply reel around which the tape is wound and the total area of the tape. The total area of the tape is the sum of the hub area of both reels projected on a plane and the area of the tape, and the reel area is the area of the hub on each reel and the area of the tape wound therearound. And the sum of the areas of both reels is the total area.

[0003] The reel area is determined by the number of tape turns or the tape diameter and the tape thickness. The tape thickness is determined by a standard, and a standard deceleration point is set so that the tape can be reliably decelerated assuming the upper limit of the standard, that is, a tape having a large tape thickness.

[0004]

At the time of FF / REW, air is entrapped, and the tape is loosely wound. Therefore, if the deceleration point is set based on the total area obtained first, the deceleration cannot be completed, and the sudden braking must be performed, and the tape may be damaged. Alternatively, if the deceleration point is set with a margin, the vehicle decelerates early and it takes time for high-speed feeding.

Therefore, during high-speed running, if a change in the reel area due to an apparent change in the tape thickness is detected and the deceleration point is set again, deceleration can be accurately performed. Speed can be safely achieved without damaging the tape.

In order to detect the reel area, two reel detectors for detecting the rotation of the take-up reel and the supply reel are provided. As a reel detector, an optical sensor such as a photo interrupter is provided for each reel,
The detected portion is provided on a reel or a member that rotates in cooperation with the reel. Then, the number of rotations of each reel is measured by detecting, with an optical sensor, light reflected or transmitted by the detected portion in accordance with the rotation of the reel. Each reel area is calculated based on the rotation speed.

[0007] If there is a molding defect in the reel or the like or a variation in the reflectance of the portion to be detected, the number of rotations of the reel cannot be accurately detected, and an accurate reel area cannot be calculated. That is, if there are two detectors, there is a possibility that the probability that the detection accuracy decreases will increase. However, when one detector is used, the reel area cannot be obtained by the conventional method, and the FF / REW at a low speed has to be performed.

In view of the above, an object of the present invention is to provide a magnetic recording / reproducing apparatus which can calculate an accurate reel area even with a single detector and can set an appropriate deceleration point when a tape is fed at high speed. For the purpose of providing.

[0009]

According to the present invention, there is provided a reel detecting means for detecting rotation of one of a supply reel and a take-up reel.
A deceleration point for high-speed feeding such as fast-forwarding or rewinding is optimally set based on outputs from two reel detecting means and a tape detecting means for detecting a tape feed amount.

More specifically, an area calculating means for calculating a reel area based on the outputs of the two detecting means, a high-speed running setting means for setting a running condition of the tape during high-speed feeding based on the calculated reel area, Running change means for temporarily resetting the running conditions by temporarily running the tape at a low speed.

According to this, by running the tape at a constant speed, the tape feed amount and the number of rotations of the reel are detected, and the reel radius can be obtained therefrom, and the reel area can be calculated. The deceleration point is set based on this.

During high-speed feeding, the apparent tape thickness may change due to air entrainment or the like.
There is a difference between the actual reel area and the initially set reel area. By reducing this difference, appropriate deceleration can be performed when approaching the tape end.

Therefore, when the tape reaches a preset deceleration point during high-speed feeding, the drive of the motor is switched so that the tape is run at a constant speed, and the reel radius is obtained during the constant-speed running. The actual tape thickness is calculated from the difference between the calculated reel radius and the initially set reel radius. Then, the subsequent deceleration points are changed based on the actual tape thickness, and the running conditions of the tape are reset. After resetting, high-speed feeding is performed again, and when the deceleration point after the change is reached, deceleration processing is performed to safely stop the tape without damaging the tape.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a magnetic recording / reproducing apparatus according to one embodiment of the present invention comprises a supply reel 2 for supplying a tape 1 and a take-up reel 3 for rewinding.
And a drive motor 4 for rotating the drive motor 3. Then, as shown in FIG.
3, the reel hubs 6 of the cassettes 5 are engaged with each other.
Further, a drive mechanism for moving the pinch roller 8 close to and away from the capstan 7 is provided, and the capstan 7 is rotationally driven by the drive motor 4. When the pinch roller 8 is set close to the capstan 7, the tape 1 is sandwiched between the pinch roller 8 and the capstan 7, and the tape is fed at a constant speed. Further, each of the reels 2 and 3 has a capstan pulley 9 from a drive motor 4.
A driving force is transmitted to the reel pulley 11 via the belt 10, and a high torque driving force is selectively transmitted by the idler 12, so that high-speed feeding is performed. The idler 12 includes a drive gear 13 integrated with the reel pulley 11 and idler gears 14 and 15 meshing with the drive gear 13. By swinging the idler 12, one of the idler gears 14 and 15 is rotated.
Meshes with the driven gear 16 of the supply reel 2 or the driven gear 17 of the take-up reel 3. Thereby, the drive transmission to the supply reel 2 or the take-up reel 3 is switched. In the figure, 18 is a cylinder, and 19 is a guide pin.

Then, reproduction, recording, and fast-forward reproduction (VS
F), a control unit 2 that controls the drive of the drive motor 4 according to each of the running modes of rewind reproduction (VSR), FF, and REW.
0, and the motor driver 21 drives the drive motor 4 at a predetermined rotation speed based on the output voltage from the control unit 20. The rotation speed of the drive motor 4 is detected by a rotation detector 22. As the rotation detector 22, for example, a frequency generator (FG) is used, generates a frequency signal corresponding to the number of rotations, and outputs the frequency signal to the control unit 20. As a result, the tape feed amount can be calculated, and the rotation detector 22 serves as a tape detecting unit.

Further, a reel detector 23 for detecting the number of rotations of the take-up reel 3 is provided. As the reel detector 23, a non-contact sensor such as an optical sensor or a magnetic sensor that generates a pulse according to the rotation of the take-up reel 3 is used. By counting the reel pulses output from the sensor, the number of rotations of the reel 3 is obtained. For example, if the reel 3 makes one rotation, the number of pulses becomes six.

A control unit 20 composed of a microcomputer
Then, the output voltage to the drive motor 4 is controlled so that the traveling speed corresponds to the input mode. In particular, FF / R
At the time of high-speed feeding of the EW, acceleration / deceleration control of the drive motor 4 is performed to make the tape 1 run at high speed. Therefore, a plurality of acceleration / deceleration sections are set from the start to the end, and the drive of the drive motor 4 is controlled.

As an example of the control, first, the drive motor 4 is accelerated to a certain rotation, and when the rotation speed is reached, the drive motor 4 keeps rotating at a constant speed. And
When a first deceleration point set based on the reel area is reached, the rotation speed of the drive motor 4 is reduced to maintain a certain rotation speed. When the second deceleration point when the end of the tape 1 is approached is reached, the rotation speed of the drive motor 4 is further reduced to maintain a constant rotation speed. When the end of the tape 1 is detected, the drive motor 4 is stopped,
Stop the tape 1 by applying the brake.

Here, the control unit 20 calculates the reel area from the outputs of the rotation detector 22 and the reel detector 23 during the constant speed running before the high speed running, and sets the deceleration point based on this. In the middle of high-speed feeding, the tape is once run at a constant speed, and the tape thickness is determined by comparing the actual reel area with the reel area calculated from the standard tape thickness. It has been changed to become.

The deceleration processing at the time of high-speed feeding will be described with reference to FIGS. First, when high-speed feeding is started, in the case of FF, the tape 1 runs at a constant speed by fast-forward playback (VSF). In the case of REW, rewind reproduction (VSR) is performed. Then, the reel pulses from the reel detector 23 are counted to calculate the number of rotations, and the tape feed amount is calculated from the count value of the frequency signal from the rotation detector 22. The reel circumference is determined from the rotation speed and the tape feed amount, and the reel radius r1 of the take-up reel 3 is obtained.
Is obtained, and the reel area can be calculated.

Thereafter, in order to determine the reel radius of the supply reel 2, the tape 1 is driven in a reverse direction at a constant speed, for example, REW.
I do. The reel pulse from the reel detector 23 is counted, and a value obtained by dividing the count value of the frequency signal of the rotation detector 22 counted simultaneously by the gear ratio is calculated. Since this value corresponds to the supply reel-side reel pulse, the rotation ratio between the supply reel 2 and the take-up reel 3 is determined from this value and the count value of the take-up reel-side reel pulse.
Since the rotation ratio = the radius ratio, the reel radius of the supply reel 2 is obtained from the reel radius r1 of the take-up reel 3. That is, the idler gear 15 and the driven gear 1 of the supply reel 2
6, the rotation of the supply reel 2 driven by the drive motor 4 is determined by the rotation ratio (both gear ratios) of the idler gear 15 and the drive motor 4, and based on this gear ratio, the take-up reel 3 side , The reel area of the supply reel 2 can be obtained without providing the supply reel 2 with a reel detector.

Based on the reel radius determined as described above, the take-up reel area, the supply reel area and the total area are calculated. As a result, the tape length of the tape to be used is determined, and the maximum tape thickness (t =
0.02 mm) as the standard tape thickness, and the first and second deceleration points are set based on this tape thickness.

When the drive motor 4 is driven so as to run at a high speed, it is determined which of the plurality of sections on which the winding reel area is preset is located, and according to the section, Count start point and count number N
Set. The count start point is the count number of the reel pulse on the winding side corresponding to the start area of the reel area on the winding side for measuring the tape thickness.
Is the count number of reel pulses on the winding side until the first deceleration point is reached.

When the vehicle travels at high speed and reaches the first deceleration point, the drive motor 4 is temporarily stopped. And VS
F, and the tape position is reconfirmed. During this time, the reel radius r of the take-up reel 3 is determined in the same manner as described above.
2 and the take-up reel area are calculated.

Then, the actual tape thickness t is determined in order to reduce the difference between the actual reel area and the standard reel area based on the standard tape thickness. That is, the tape thickness t is calculated from t = (r2−r1) / N. The second deceleration point thereafter is reset based on the tape thickness t. That is, if the actual reel area is larger than the standard reel area,
The state is such that the apparent tape thickness is large, and the second deceleration point is changed to be earlier. If the actual reel area is small, the apparent tape thickness is small,
Change the deceleration point so that it is later.

The high-speed running is again performed, and when the changed second deceleration point is reached, the rotation speed of the drive motor 4 is reduced and the drive motor 4 is rotated at a low speed, and the tape runs slowly. 4 is stopped, and the tape 1 is stopped by applying a brake.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that many modifications and changes can be made to the above-described embodiment within the scope of the present invention. Although the case of the FF has been described above, in the case of the REW as well, high-speed REW can be performed by indirectly obtaining the reel radius of the supply reel using the rotation detector.

Although the reel detector is provided only for the take-up reel, it may be provided only for the supply reel.
This case can be dealt with by exchanging the processing of FF and REW in the above embodiment. Further, the tape feed amount may be calculated by directly detecting the running of the tape using an optical sensor, a magnetic sensor, or the like instead of the rotation detector.

[0029]

As is apparent from the above description, according to the present invention, the deceleration point in high-speed feeding can be appropriately set even if only one reel detector is required, which is required in the past. Safe high-speed feeding can be realized. Therefore, by reducing the number of detectors, the number of wirings can be reduced, and the number of parts and cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 (a) is a view showing tape running during high-speed feeding,
(B) The figure which shows the drive transmission mechanism to a reel.

FIG. 3 is a flowchart of a deceleration process during high-speed feeding.

FIG. 4 is a diagram showing the operation timing of a drive motor during high-speed feeding.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 tape 2 supply reel 3 take-up reel 4 drive motor 20 control unit 22 rotation detector 23 reel detector

Claims (2)

[Claims] 1. A supply reel for sending out a tape, a take-up reel for winding the tape, a motor for rotating and driving the take-up reel, a reel detecting means for detecting rotation of one of the reels, and a tape. Tape detecting means for detecting a feed amount, area calculating means for calculating a reel area based on outputs from both detecting means, and tape running conditions at the time of fast-forward or rewind are set based on the calculated reel area. A magnetic recording / reproducing apparatus comprising: high-speed running setting means; and running changing means for temporarily resetting running conditions by causing the tape to run at a low speed during fast-forward or rewind. 2. A supply reel for sending out a tape, a take-up reel for winding the tape, a motor for rotating the take-up reel, a reel detecting means for measuring the rotation of one of the reels, and a tape. Tape detecting means for detecting a feed amount, area calculating means for calculating a reel area based on outputs from both detecting means, and tape running conditions at the time of fast-forward or rewind are set based on the calculated reel area. High-speed running setting means, running switching means for temporarily stopping when a preset deceleration point is reached during fast-forward or rewind, and then running the tape at a low speed, and calculating the actual reel area during low-speed running. Resetting means for resetting the running condition of the tape based on the actual reel area, and a running means for fast-forwarding or rewinding under the running condition after resetting. A magnetic recording / reproducing apparatus comprising: a step;