JPH0760591B2 - Tape thickness measuring device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a tape thickness measuring device suitable for use in measuring the thickness of various tapes on which audio signals, video signals, etc. are recorded.

[Outline of Invention]

According to the present invention, the reel is sent at a constant speed and the time T ₀ of the cycle is measured, and then the reel is rotated at a predetermined speed by a predetermined amount and then sent at a constant speed again to send the time T _{n of the} same reel cycle as before. ′ Is measured, and the measured T ₀ and T _n ′ are substituted into a predetermined formula to accurately obtain the tape thickness of the tape.

[Conventional technology]

As an example of a conventional tape thickness measuring method, for example, a tape is fed at a constant speed, the sum of squares of the periods of the winding side reel and the supply side reel is calculated, and the type of the tape is specified by this value. Using the standard value of the total tape length of each type of tape, the tape thickness D is calculated by the following equation.

In the above formula (1), Vt is the tape speed, T _T is the rotation cycle of the winding reel, T _S is the rotation cycle of the supply reel, r ₀ is the hub radius of the reel, and L ₀ is the total tape length.

[Problems to be solved by the invention]

However, in the case of the conventional method as described above, even if the given tape total length is slightly different from the standard value of the tape,
If it is determined that the tapes are of the same type at the stage of grouping the types of the tapes, the standard value of the tapes is applied thereafter and the calculation proceeds, so that an error occurs in the tape thickness D of the tapes. There is an inconvenience.

The present invention has been made in view of the above circumstances, and provides a tape thickness measuring device capable of accurately obtaining the tape thickness even if the total tape length is unknown.

[Means for solving problems]

A tape thickness measuring device according to the present invention comprises a plurality of reels around which a magnetic tape is wound, a rotation detecting means for detecting the rotation of the plurality of reels, and a rotation of the reel based on an output pulse from the rotation detecting means. Control means for controlling,
The control means travels the tape at a constant speed for a predetermined output pulse from an arbitrary position, measures the time T ₀ of the reel rotation cycle, runs at a high speed so as to be separated by a predetermined distance, and then re-taps the tape for a predetermined output pulse. The tape is allowed to travel at a constant speed, the time T _n ′ of the rotation cycle of the reel is measured, and the tape thickness D is obtained based on the following equation.

Where Vt is the tape speed at constant speed, n is the number of output pulses from the start of measurement at time T _{0 to} the start of measurement at time T _n ′, and k is time.
T _n ′, the number of output pulses required for measuring the time T ₀ , and m is the number of pulses output from the rotation detecting means when the reel makes one rotation.

[Action]

The tape (3) is sent at a constant speed at an arbitrary position, and among the reels (1) and (2) on which the tape is wound, the time T ₀ of the shorter reel cycle is detected as the reel rotation. Bowl (1
Measure by counting the number of pulses from 5) or (16). Next, the reel for which T ₀ is obtained at an arbitrary speed is rotated by a predetermined wave number, the tape is run at a high speed so as to be separated by a predetermined distance, and then the tape is fed again at a constant speed to obtain the reel cycle time T _n ′ of the reel. , It is measured by counting the number of pulses from the reel rotation detector. Then, using the measured times T ₀ and T _n ′, the tape thickness D is calculated based on a predetermined formula.

〔Example〕

An embodiment of the present invention will be described below in detail with reference to FIGS.

First, the basic principle of the present invention will be described with reference to FIGS. 4 and 5.

When the tape is run at a constant speed, the reel cycle of the shorter reel cycle of the take-up side reel and the supply side reel is determined and set as T ₀ . In the case of FIG. 4, since the magnetic tape (3) is wound around the supply reel (1) less than the take-up reel (2), the supply reel (1) has a shorter reel cycle. I understand. Therefore, the reel cycle of this supply side reel (1) is obtained and set as T _S0 .

At this time, if the winding diameter of the supply-side reel (1) is r _S , the reel hub diameter (radius) is t ₀ , and the tape speed is Vt, the reel cycle
T _S0 is expressed by the following equation.

As shown in FIG. 5 from the state of FIG. 4, when the reel cycle after the supply-side reel (1) is turned n times is T ′ _S , the following equation is obtained.

However, in the above formula (3), r ′ _S is the winding diameter of the supply side reel (1) after n turns. When the tape thickness is D between the winding diameters r _S and r ′ _S , there is a relationship of r ′ _S = r _S + n · D (4), and therefore the above (2) to (3) The following equation is obtained from the equation.

From equation (5) above, the tape thickness D is expressed as follows.

In the above (6), T _'S, T _S0 is the rotation detector and the like attached to the reel table, be obtained if supplied capable of time measured as a microcomputer or the like that outputs Tekiru. Whether or not n turns have been made can be determined by counting the number of pulses from the rotation detector. Further, the tape speed Vt is a known and constant. Therefore, from the above, it is understood that the tape thickness D can be obtained from the above equation (6).

Also, except when measuring the reel cycles T _S0 and T ′ _S , Vt
Since it is not necessary to feed the tape at a high speed, fast-forward (FF) or rewind (REW) is sent at high speed until n turns after measuring T _S0, and after n turns, it is sent again at a speed of Vt and the reel cycle T _'may be to determine the _S. As a result, the time for _{obtaining the} reel cycles T _S0 and T ′ _S is shortened, and the tape thickness can be obtained in a short time.

And, contrary to the case of FIGS. 4 and 5, the reel cycle
If the cycle of the take-up reel is short when measuring T ₀ , the reel cycle of the take-up reel is stored as T _T0 . After that, the reel side of the take-up reel is measured n times after the take-up reel has made n turns, and is given as T _T ′. The tape thickness D can be obtained from the above equation (7).

That is, according to this basic principle, the tape thickness D is obtained when the reel cycle is one rotation.

Next, how to obtain the tape thickness D when the reel cycle is any rotation other than one rotation will be described with reference to FIG.

Here, the number of output pulses output from the rotation detector when the reel makes one rotation is m waves. Also, reel cycle
The number of waves required to measure T ₀ and T _n ′ is k wave. T ₀ is the reel cycle at the time of the minimum constant speed feeding, and T _n ′ is the reel cycle at the constant speed feeding after feeding the tape corresponding to nk waves thereafter. Therefore, if each reel cycle T ₀ , T _n ′ is converted into one cycle, Becomes Further, n represents the wave number from the start of measurement of the reel cycle T _{0 to} the start of measurement of the reel cycle T _n ′. Therefore,
N waves correspond to n / m turns. By substituting these relationships into the above equation (6), the following equation is obtained.

It can be seen from the above equation (8) that the tape thickness D can be similarly obtained even when the reel cycle is arbitrarily rotated.

FIG. 1 shows a specific circuit configuration when the tape thickness D is obtained by arbitrarily rotating the reel cycle. In FIG. 1, (1) is a supply side reel, (2) is a winding side reel,
(3) is a magnetic tape wound between these reels. The reels (1), (2) are respectively reel motors (4),
It is rotationally driven by (5). The reel motors (4) and (5) are driven and controlled by the reel motor control circuit (6).

Further, (7) is a capstan, (8) is a capstan motor for rotationally driving the capstan (7), and (9) is a capstan motor control circuit for driving and controlling the capstan motor (8). (10) is a pinch roller provided for the capstan (7), (11) is a spring stretched around the pinch roller (10), and (12) is a pinch against the elastic force of the spring (11). A plunger circuit for controlling the roller (10), (13) a system control circuit including a microcomputer for supplying various control signals to the control circuits (6), (9) and the plunger circuit (12), and (14) a tape Information from (3) system control circuit (13)
Heads (15) and (16) supplied to the reels are rotation detectors for detecting the rotation of the reels (1) and (2), respectively.

Next, the circuit operation of FIG. 1 will be described with reference to the flowchart of FIG. In step (a), the operation starts, and in step (b), the system control circuit (1
Reel motor control circuit (6) by control signal from 3)
Is controlled to drive the reel motors (4) and (5) to bring the reels (1) and (2) into a rotationally driven state. Further, the capstan motor control circuit (9) is controlled by a control signal from the system control circuit (13) to drive the capstan motor (8) to rotationally drive the capstan (7) and the system control circuit (13). The control circuit outputs the plunger circuit (12) to press the pinch roller (10) against the capstan (7) against the elastic force of the spring (11). Then, the magnetic tape (3) is clamped by the capstan (7) and the pinch roller (10) and is fed at a constant speed, for example, forward feed.

In step (c), pulse signals from the rotation detectors (15) and (16) that detect the rotation of the reels (1) and (2) are supplied to a system control circuit (13) using a microcomputer, Of these pulse signals, the time of the output k-wave from the shorter rotation detector is measured,
The time of the reel cycle (the time when a predetermined number of pulses are output from the rotation detector, that is, the time required for the reel to rotate a predetermined rotation angle) T ₀ is calculated, and the system control circuit (13)
Store in internal memory.

In step (d), the system control circuit (13) deactivates the plunger circuit (12) to release the pinch roller (10) from the pressure contact with the capstan (7) and control the reel motor control circuit (6). Then, the magnetic tape (3) is sent from the k-th wave at an arbitrary speed for nk waves.

In step (e), under the control of the system control circuit (13) again, constant-speed feeding is performed, and the reel cycle time (the time when a predetermined number of pulses are output from the rotation detector, that is, the reel A pulse signal from the rotation detector on the reel side, which has obtained T ₀ around a predetermined rotation angle), is supplied to the system control circuit (13), the time of the output k wave from the rotation detector is measured, and the reel is measured. Cycle time
T _n ′ is obtained and stored in the memory in the system control circuit (13).

At step (f), the reel cycle times T ₀ , T stored in the memory of the system control circuit (13)
_The tape thickness D is obtained by taking out _n ′ and using this to calculate according to the equation (8). However, the tape speed Vt at a constant speed, the wave number n from the start of measurement at time T _{0 to} the start of measurement at time T _n ′, wave number k required for measurement at times T ₀ and T _n ′, and wave number m per revolution It is assumed that the constant of is previously input to the memory as information. Then, in step (g), a series of operations is completed.

As a result of the determination in this way, in the conventional tape cassettes classified into types, one representative value (standard value) was applied to all the tape cassettes belonging to that type as the value of the total tape length. In the example, since the tape thickness is obtained by using the times T ₀ and T _n ′ of the reel cycle which are individually measured, the tape thickness can be accurately obtained even if the total length of the tape is unknown.

In the example of FIG. 2 described above, the constant speed feeding of the tape is the forward feeding, but the tape may be fed at a speed several times faster than this to obtain the reel cycle time.
At that time, the value of Vt in the above (8) is changed correspondingly.

〔The invention's effect〕

As described above, according to the present invention, a tape having an unknown tape length is fed at an arbitrary position at a constant speed, the time T ₀ of the cycle of the shorter reel is measured, and then the reel for which T ₀ is obtained is determined. The tape is fast-forwarded or rewound at a high speed so as to be fed by a predetermined amount and separated by a predetermined distance, and then is fed at a constant speed again, and the time T _n ′ of the reel cycle at that time is measured, and these T ₀ and T _n ′ are calculated. Since the tape thickness D is obtained from the predetermined formula by using the tape thickness, the tape thickness can be accurately obtained in a short time even if the tape has an unknown tape length.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a flow chart for explaining the operation of FIG. 1, FIG. 3 is a schematic diagram for explaining the present invention, and FIG. 5 and 5 are schematic diagrams for explaining the basic principle of the present invention. (1) is a supply side reel, (2) is a winding side reel,
(3) is a magnetic tape, (4) and (5) are reel motors,
(6) is a reel motor control circuit, (7) is a capstan, (8) is a capstan motor, (9) is a capstan motor control circuit, (13) is a system control circuit, and (15) and (16) are It is a rotation detector.

Front Page Continuation (72) Inventor Toshiyuki Tani, 6-735 Kitashinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Inventor Shigeyuki Satomura 6-7-35, Kitashinagawa, Shinagawa-ku, Tokyo Sony Corporation Shares In the company

Claims (1)

[Claims] 1. A plurality of reels around which a magnetic tape is wound, rotation detecting means for detecting the rotation of the plurality of reels, and rotation of the reel is controlled based on an output pulse from the rotation detecting means. Comprising a control means, the control means to run the tape at a constant speed for a predetermined output pulse from an arbitrary position, to measure the time T ₀ of the reel rotation cycle,
After running at a high speed so as to be separated by a predetermined distance, the tape is run again at a constant speed for the above-mentioned predetermined output pulse, the time T _n ′ of the reel rotation cycle is measured, and the tape thickness D is obtained based on the following equation. The tape thickness measuring device characterized in that Where Vt is the tape speed at constant speed, n is the number of output pulses from the start of measurement at time T _{0 to} the start of measurement at time T _n ′, and k is time.
T _n ′, the number of output pulses required for measuring the time T ₀ , and m is the number of pulses output from the rotation detecting means when the reel makes one rotation.