JPH05307800A - Tape tension controller - Google Patents

Abstract

PURPOSE:To unnecessitate a tension pin and a tension arm by providing a load torque sensor for a supply reel disk and a winding diameter detection sensor for supply reel on the circumference of supply reel part. CONSTITUTION:An upper side reel disk 18 integrally rotating with the supply reel 4 and a lower side reel disk 19 pressed by a brake 7 are arranged, and rotating sensors 21, 22 are provided respectively on the disks 18, 19. By this constitution, the amount of load of the brake 7 is detected as the phase difference of the output voltages of sensors 21 and 22. Also, the number of rotation for the supply reel 4 is measured as the number of rotation for the disk 18 or 19 therefrom the tape winding diameter is calculated. The phase difference to supply an adequate tension corresponding to the tape diameter is obtained by the calculation or experiment and kept inputting to a storage part of an objective phase output circuit. Thus, by means of controlling so that the objective phase difference is obtained, the tape tension is controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape tension control device for a recording / reproducing apparatus.

[0002]

2. Description of the Related Art FIG. 21 is a plan view showing a conventional magnetic recording / reproducing apparatus disclosed in Japanese Utility Model Laid-Open No. 2-105246. 22 is a perspective view showing a state in which the deck portion of the magnetic recording / reproducing apparatus is incorporated in the substrate based on FIG. In addition, the tension arm 16 is arranged so that the rotary shaft 15 can be seen.
Fractured around 15. In FIG. 23, the substrate of FIG. 22 is omitted, and a state is shown in which the tape series guide member between the two reels to which the tape is transferred is moved upward. Hereinafter, description will be given with reference to FIGS. 21 to 23. In FIG. 22, 1
Is the base substrate that forms the deck. Reference numeral 2 is a tape on which information is recorded / reproduced by a magnetic recording / reproducing apparatus, 3 is a cassette for accommodating the tape 2 and attached to / detached from the substrate 1, 4 is accommodated in the cassette 3, and the tape 2 is wound around and rotatable. Is a supply reel supported by. Reference numeral 5 denotes a rotary shaft vertically provided in parallel on the substrate 1, 6 denotes a supply reel disk rotatably supported around the rotary shaft 5, and 7 denotes a side surface on which the supply reel disk 6 rotates. A brake which adjusts the load by pressing against, a lower surface of which is fixed to the substrate 1 and which is in sliding contact with the tape 2 while rotating and which magnetically records and reproduces information on the tape 2, 9 is a rotary cylinder of the rotary cylinder 8. A magnetic head, which is installed around the rotating surface and contacts the tape 2 for magnetic recording and reproduction, 10
Is placed on the substrate 1 and is in contact with the tape 2,
Is a capstan for transferring the tape at a constant speed, 11 is installed on the substrate 1 at a position in contact with the capstan 10 at the time of recording / reproducing, and a pinch roller for nipping and transferring the capstan 10 and the tape 2, and 12 is the supply reel. Cassette 3 in parallel with 4
A take-up reel that is housed inside and is rotatably supported by winding the tape 2, a take-up reel disk 13 that is rotatably supported around the rotating shaft 5, and 15 is on the substrate 1. The rotating shaft provided, 16 is rotated around the rotating shaft 15,
A tension arm on which a tension pin 14 is erected, 14 is a tension pin that contacts the tape 2 and rotates about an axis vertically installed on the substrate 1 in proportion to the tension applied to the tape 2, A spring that is hung between the tension arm 16 and the substrate 1 and biases the tension arm 16 in the counterclockwise direction in the figure.

Next, the operation will be described. In FIG. 23, the tape tension of the tape 2 is controlled by adjusting the load on the supply reel disk 6 by the brake 7. The tape tension is detected by detecting the rotation angles of the tension pin 14 and the tension arm 16 that contact the tape 2. When the tension arm 16 rotates, the load on the supply reel disc 6 is adjusted by the brake 7 via the members around the supply reel disc 6 drawn below the supply reel 4.
When the tension of the tape 2 is higher than the set value, the tension pin 14 is pressed and the tension arm 16 rotates rightward in the figure together with the tension pin 14 with respect to the rotary shaft 15.
When the tension arm 16 rotates to the right, the pressing of the supply reel disc 6 by the brake 7 decreases,
The rotational load of the supply reel disk 6 is reduced, and thus the tension of the tape 2 is reduced to the set value.

On the other hand, when the tension of the tape 2 is reduced with respect to the set value, the tape 2 reduces the pressing force against the tension pin 14, and the tension arm 16 is integrated with the tension pin 14 and the tension of the spring 17 causes the rotary shaft to rotate. 15 rotates counterclockwise in the figure, the pressing by the brake 7 increases, the rotational load of the supply reel disk 6 increases, and the tension of the tape 2 increases to the set value.

[0005]

Since the conventional tape tension control device is constructed as described above, it is necessary to dispose the tension pin and the tension arm on the deck in order to control the tape tension. There is a restriction on the arrangement of the transfer mechanism, which is a restriction for downsizing the deck of this magnetic recording / reproducing apparatus.

The present invention has been made in order to solve the above-mentioned problems, and is intended to eliminate the tension pin from the tape tension control device and to downsize the deck of the magnetic recording / reproducing device. Is.

[0007]

[Means for Solving the Problems] Instead of directly detecting the tape tension, the load torque on the supply reel disk is detected. Therefore, a mechanism for generating a displacement proportional to the load torque is added to the supply reel disc to detect the load torque as the displacement of the supply reel disc. Further, by detecting the load torque applied to the supply reel disk and the supply reel winding diameter calculated from the supply reel rotation speed, the target value of the load torque is set as a value corresponding to the supply reel winding diameter.

[0008]

The tension pin and the tension arm that come into contact with the tape are arranged by arranging a sensor for load torque to the supply reel disk and a sensor for detecting the supply reel winding diameter on the deck of the magnetic recording / reproducing apparatus around the supply reel portion. (EN) A tape tension control device capable of detecting and controlling a load on a tape without using.

[0009]

【Example】

Example 1. An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing the entire structure, and 18 is rotatably supported by a rotary shaft 5 provided on the substrate 1, and when the cassette 3 is mounted, it is located below the supply reel 4 like the supply reel disk 6. It is an upper reel disc that fits in and rotates coaxially. Reference numeral 19 denotes a lower reel disk which is rotatably fitted to the lower surface and the inner circumference of the upper reel disk 18 and rotates coaxially with the upper reel disk 18.
20 indicates the upper reel disc 18 and the lower reel disc 19
Is a biasing member that biases the rotary shaft 5 in the circumferential direction.

2 to 3 show the upper reel disc 18 described above.
And the assembly structure of the lower reel disk 19 are described in detail. In the drawing, 27 is two spring hooks projecting from the upper reel disk 18, and 28 is two spring hooks projecting from the lower reel disk 19. , 29 are two oblong holes provided in the lower reel disc 19, and the spring hook 27 penetrates through these oblong holes 29.
Two springs 20 are stretched between the spring hooks 27 and 28.

FIG. 4 is a vertical sectional view of the upper reel disk 18 and the lower reel disk 19, and FIG. 5 is a view taken in the direction of arrow V in FIG. 4, in which 21 is fixed to the substrate 1. The upper rotation sensor is arranged at a position facing a magnet magnetized in the upper surface of the upper reel disk 18 and magnetized in the circumferential direction. Reference numeral 22 denotes a lower rotation sensor fixed to the substrate 1, and is arranged at a position facing a magnet magnetized in the lower surface of the lower reel disk 19 and magnetized in the circumferential direction. An upper magnet 30 is attached to an outer peripheral position of the upper reel disk 18, faces the upper rotation sensor 21 in the vertical direction, is magnetized N and S in the vertical direction, and has 1 or more m poles in the circumferential direction. A lower side which is attached to the outer peripheral position of the lower reel disk 18 and which vertically opposes the lower rotation sensor 22 and is magnetized in the vertical direction by N and S and has a number of poles n in the circumferential direction. It is a magnet.

In FIG. 1, reference numeral 26 is a transmission mechanism rotatably supported by a fixed shaft provided on the substrate 1, and 7 is fixed to the transmission mechanism 26 and is attached to the outer peripheral surface of the lower reel disk 19. This is a brake that comes into contact when necessary. An actuator 25 is fixed to the substrate 1 and can rotate the transmission mechanism 26 as needed.
Reference numerals 23 and 24 denote sensor output synthesizing circuits and actuator driving circuits for calculating outputs of the upper side rotation sensor 21 and the lower side rotation sensor 22 and driving the actuator 25. FIG. 6 is a block diagram showing this arithmetic circuit. ing.

In FIG. 6, 42 is the output of the lower rotation sensor.
A winding diameter calculation circuit that calculates the tape winding diameter of the supply reel 4 from 33. 43 is a target phase output circuit that outputs a target phase difference corresponding to the magnitude of the output of the winding diameter calculation circuit 42.
Is a phase output circuit that outputs a phase difference 38 from the upper rotation sensor output 32 and the lower rotation sensor output 33, and 45 compares the output of the target phase output circuit 44 and the output of the phase output circuit 44 with the error signal. It is a comparison circuit that inputs to the actuator drive circuit.

The operation of one embodiment will be described below. The operation of the upper reel disc 18, the lower reel disc 19, and the biasing member 20 will be described with reference to FIGS. 2 and 3. A case where the load applied to the lower reel disc 19 by the brake 7 becomes larger than the regulation will be described. The upper reel disc 18 receives a left rotation moment in FIG. 2 with respect to the lower reel disc 19, and the spring hook 27 extends the biasing member 20 and moves along the elongated hole 29. Tape 2 acting on supply reel 4
Similarly, when the tension due to is increased, the upper reel disk 18 receives the moment of left rotation in FIG.
Extend 20 and move along slot 29. as a result,
The tension of the biasing member 20 balances the load of the brake 7 and the tension of the tape 2 acting on the supply reel 4.

Brake 7 for lower reel disk 19
The case where the load due to is smaller than the specified value will be described. The spring hook 27 moves along the elongated hole 29 by receiving a moment of clockwise rotation in FIG. 2 due to the tension of the biasing member 20. That is, the upper reel disc 18 rotates to the right in the figure with respect to the lower reel disc 19. Similarly, when the tension applied by the tape 2 acting on the supply reel 4 becomes small, the upper reel disc 18 rotates clockwise relative to the lower reel disc 19 in FIG. The tension of the biasing member 20 balances the load of the brake 7 and the tension of the tape 2 acting on the supply reel 4.

The detection mechanism of the upper rotation sensor 21 and the lower rotation sensor 22 will be described with reference to FIGS. The magnitude of the load on the brake 7 is detected as the phase difference between the upper reel disk 18 and the lower reel disk 19, that is, the phase difference between the output voltage of the upper rotation sensor 21 and the output voltage of the lower rotation sensor 22. The rotation speed of the supply reel 4 is measured as the rotation speed of the lower reel disk 19 by the lower rotation sensor 22 or as the rotation speed of the upper reel disk 18 by the upper sensor 21.

A method of detecting the cycle 39 of the supply reel 4 and the phase difference 38 between the upper reel disk 18 and the lower reel disk 19 will be described. The cycle of the supply reel 4 is calculated in the winding diameter calculation circuit 42 shown in FIG. 6, and the lower sensor pulse 37 indicates the time when the value of the lower rotation sensor output 33 becomes the threshold value 35 or more as a width. It can be obtained by detecting the interval at which the upper sensor pulse 38 is generated or the interval at which the upper sensor pulse 38 is generated, the interval being the width at which the value of the upper rotation sensor output 32 becomes the threshold value 34 or more.
7 and 8, the period 39 is shown as the interval at which the lower sensor pulse 37 is generated. The phase difference 38 between the upper reel disk 18 and the lower reel disk 19 is calculated in the phase output circuit 44, and the upper sensor pulse 36 and the lower sensor pulse
Detected as an interval with 37. 7 and 8, the phase difference 38 is shown by the time interval between the falling edge of the lower sensor pulse 37 and the falling edge of the upper sensor pulse. FIG. 7 shows a case where the load on the supply reel disc 19 is large, and the phase difference 39 is larger than that when the load on the supply reel disc 19 shown in FIG. 8 is small.

A method of inputting the lower rotation sensor output 33 and outputting the tape winding diameter D in the winding diameter calculating circuit 42 of FIG. 6 will be described. Since the number of magnetic poles of the lower magnet 31 is n, the tape length sent out by 1 / n rotation of the supply reel 4 is divided by π, that is, the prescribed tape speed × period / n / π = tape winding diameter Obtained as D. A method of receiving the output of the winding diameter calculation circuit 42 in the target phase output circuit 43 and outputting the data of the phase difference 39 to be the target according to the data of the storage circuit section will be described. The target phase output circuit 43 stores the data of the phase difference 39 corresponding to the tape winding diameter D in the internal storage circuit section. Phase difference 39 corresponding to tape winding diameter D and giving appropriate tape tension
Of the target phase output circuit
Input to 43 memory circuit. The comparator circuit 45 outputs a difference signal between the target phase output circuit 43 and the phase output circuit 44 with a positive value when the target phase output circuit 43 is larger than the phase output circuit 44, and the target phase output circuit 43 outputs the difference signal. If smaller, it outputs a difference signal between the target phase output circuit 43 and the phase output circuit 44 with a negative value.

Functions other than the sensor output synthesis circuit 23 will be described with reference to FIG. The actuator drive circuit 24 receives the output of the comparison circuit 45, amplifies and adjusts the input signal for driving the actuator 25, and outputs the amplified input signal. With respect to the current position of the brake 7, if the output of the comparison circuit 45 is positive, the brake 7 is further pushed, and if the output of the comparison circuit 45 is negative, the brake 7 is released. Thereafter, the actuator 25 receives the output of the actuator drive circuit 24, operates the transmission mechanism 26, and the transmission mechanism 26 decelerates and increases the torque for precise and efficient adjustment, and drives the brake 7 to press the lower reel disk 19. Adjust. As described above, a series of tape tension control devices from the detection of the load on the lower reel disc 19 due to the phase difference between the lower reel disc 19 and the upper reel disc 18 to adjustment of the load to the target lower reel disc 19 Behavior was demonstrated.

Example 2. In addition, in order to suppress the load of the brake 7 and the fluctuation of the tension of the tape 2 as compared with the above embodiment, the upper reel disc 18 and the lower reel disc 18 are further
A tension control system in which magnets are added to the respective facing surfaces of 19 will be described as another embodiment. 9 to 12 are views for explaining the size of the gap between the upper magnet 30 and the lower magnet 31 in association with the size of the load on the supply reel disk 6. In FIG. 9 and FIG. 11, 31a is a magnet A indicating a specific lower magnet facing the specific upper magnet 30, and 40 is a small gap indicating a small gap between the upper magnet 30 and the lower magnet 31,
In FIGS. 10 and 12, 41 is a large gap indicating a large gap between the upper magnet 30 and the lower magnet 31. The distance between the upper magnet 30 and the lower magnet 31 changes in the circumferential direction.

Next, the operation will be described with reference to FIGS. 9 to 12. 9 and 11 show a case where the load variation of the brake 7 and the tension variation of the tape 2 are large. By increasing the attraction force by reducing the distance between the upper magnet 30 and the lower magnet 31, the mutual resistance between the upper reel disc 18 and the lower reel disc 19 against the load fluctuation of the brake 7 and the tension fluctuation of the tape 2 is increased. It is increased to suppress the load fluctuation. Here, if the upper magnet 30 and the lower magnet 31
When the suction force between the upper reel disc 18 and the lower reel disc 19 is constant or absent, the biasing member 20 is vibrated.
Are relatively varied in phase. Therefore, fluctuations due to the load of the brake 7 and the tension of the tape 2 cannot be suppressed.

10 and 12 show the case where the load fluctuation of the brake 7 and the tension fluctuation of the tape 2 are small. By increasing the distance between the upper magnet 30 and the lower magnet 31 to weaken the attractive force, it responds to the load fluctuation of the brake 7 and the tension fluctuation of the tape 2, and the upper reel disk
The mutual resistance between 18 and the lower reel disk 19 is reduced to suppress load fluctuation. Here, if the attraction force between the upper magnet 30 and the lower magnet 31 is constant or absent, the upper reel disc 18 and the lower reel disc 19 become the same as the conventional supply reel disc 6 of the integrated structure, and the brake 7 of the brake 7 operates. It is not possible to suppress variations in load and tension of the tape 2.

Example 3. Although the tape tension control method obtained by changing the configuration of the conventional supply reel disk 6 has been described in the above embodiment, in order to improve the performance and reliability of the tape tension control by measuring the tape driving force in real time, Furthermore, a tension control system in which the capstan motor 10 is added to the configuration will be described as another embodiment.

FIG. 13 shows the configuration of a tape tension control device corresponding to the third embodiment. In the figure, reference numeral 46 is a monitor cable extending from the capstan 10 to the sensor output combining circuit 23 for detecting the capstan current. The main structural difference of this embodiment from the above-mentioned embodiment is that the monitor cable 46 is joined. In the figure, the arrangement of the monitor cable 46 on the substrate 1 has no meaning in the description of this embodiment, and therefore the monitor cable 46 is not attached to the substrate 1.

FIG. 14 is a measurement result of the capstan drive load current in the magnetic recording / reproducing apparatus. When the capstan 10 alone is rotated, when the pinch roller 11 presses the capstan 10, the tape drive is performed. It is the figure shown about the case where a load was added. The abscissa axis showing the time shows the lapse of time from the state in which the tape 2 is completely wound on the supply reel 4 to the state in which the tape 2 is completely transferred to the winding reel 12. In the figure, 47 is a single current indicating a capstan drive load current by itself, 48 is a pinch load current indicating a capstan drive load current when the pinch roller 11 is pressure-bonded to the capstan 10, and 49 is a tape drive load component. Is a tape drive current representing the capstan drive load current, and 50 is a load current showing a value obtained by adding the pinch load current 48 and the tape drive current 49 corresponding to the capstan drive load current during recording and reproduction.

FIG. 15 shows the difference between this embodiment and the above embodiment in terms of function. Sensor output forming circuit in this embodiment
The inside of 23, the relationship between the sensor output shaping circuit 23 and the capstan 10 is shown by a block diagram. In the figure, 51
Is a reel load calculation circuit that calculates and outputs the load of the brake 7 on the reel 4 using the output of the phase output circuit 44 and the output of the winding calculation circuit 42. Reference numeral 52 is a tape tension calculation circuit for converting the tape drive current 49 from the load current 50 in the capstan 10 and calculating and outputting the tape tension. T _{C, n}
Is the output of the tape tension calculation circuit 52, and the subscript n is tension data indicating that it is the nth output data after the start of the recording / reproducing operation. T _{B, n-1} and T _{B, n} are outputs of the reel load calculation circuit 51, which are reel load data which are n−1 and n-th output data after the start of the recording / reproducing operation, respectively. <TB _{, n} > is the output of the comparison circuit 45, is also a target value for the reel load TB _{, n} , and is the target reel load data output for the nth time after the start of the recording / reproducing operation.

16 to 20 show a reel load calculation circuit.
FIG. 6 is a diagram showing the relationship among the data inside the 51, the tape tension calculation circuit 52, and the comparison circuit 45 in order as time passes after the start of recording and reproduction. In the figure, the horizontal axis is the tension data T _{C, n} ,
The target tension data <TC _{, n} > is tension data, and the vertical axis represents reel load data TB _{, n} and target reel load data <TB _{, n} > reel load data. Regarding the elapsed time, t ₀ is the recording / reproducing start time, and t ₁ is the tension data T _{C, 1} and the reel load data T _{B, 1 for the first} time after the recording / reproducing is started.
Time t ₁ that outputs, t _n is the time t _n for outputting a recording start after n-th tension data T _{C, n,} reel load data T _{B, n.}

FIG. 16 shows the time point of t = t ₀ ,
<T _C > is the target value of the tension data T _{C, n} , which is the target tension.
The value obtained by calculation or experiment is stored in the comparison circuit 45. <T _B> is the target reel load value temporarily set when recording starts, the tape material, the reel weighted average value stored in the appropriate reel load calculating circuit 51 in consideration of the temperature and humidity,
<TB _{, 0} > is the target reel load at the start of the recording / playback operation, and the reel load average value of the reel load data TB _{, n} <
T _B >, the initial target reel load recorded in advance in the reel load calculation circuit 51, <T _{c, 0} > is the target tension at the start of the recording / reproducing operation, which is equal to the target tension <T _c >, The initial target tension stored in the tension calculation circuit 52.

In FIGS. 17 and 19, t = t ₀ , t = t _n-1.
Reel load data at T _{B, 0} , T _{B, n-1} , tension data T
_{c, 0, T c, n} -1 and each time the target reel load <T _{B, n>,} indicating a relevant target tension <T _C>. 18 and 20, t = t
₁ , reel load data T _{B, 1} , T _{B, n} at t = t _n , tension data T _{C, 1} , T _{C, n} and target reel load for each time <
T _{B, 1} ＞, 〈T _{B, n} 〉 Each time target reel load 〈
T _{B, 1} >, <T _{B, n} > target tension calculated each time <T _{B, 1} >, <T _{B, n} > target tension calculated each time <T _{C, 1} >, <T _{C, n} >.

16 to 20, the points representing the coordinates are as follows. <P ₀ > is the coordinates and the initial target tension <T _{C, 0} > and the initial target reel load <T _{B, 0} >. Initial target point corresponding to, P _n is the tension data T as coordinates
Data points corresponding to _{C, n} and reel load data T _{B, n} ,
<P> is a target point corresponding to the target tension <T _C> the reel weighted average value as the coordinates _{<T B>, <P n} > each time the target tension is as coordinate <T _{C, n>} and each time the target reel load <T _{B, n} 〉
It is the target point each time corresponding to.

The operation of this embodiment will be described below. FIG.
With the configuration shown in, the capstan 10 drives the tape 2 at a constant speed, but when the tension of the tape 2 changes, the load changes,
The tape tension can be detected as the tape drive current 49. On the other hand, the lower reel disk 19 and the brake 7 can adjust the tape tension to the tape 2 by adjusting the mutual pressing.
Therefore, the tape drive current 49 is set as a control target, and the pressing of the lower reel disk 19 and the brake 7 is set as a control target, whereby the tape tension control device is configured. At that time, the effect of the pressing control of the lower reel disk 19 and the brake 7 and the relative change of the tape drive current 49 are reflected in the control target moment by moment. That is, each time the target reel load <TB _{, n-1} > was set as the target value in the past reel load data, and the result was the error in the reel load data TB _{, n-1} and the target value in the tension data. target tension <T _c> and tension data T _C is a _result, the ratio of errors of _n-1 is, each time the target reel load a target value for the current reel load data <T _{B, n>} and results in It is assumed that the ratio between the error of a certain reel load data T _{B, n} and the target tension <T _c > that is the target value in the tension data and the error of the resulting tension data T _{C, n} is equal. After that, the error between the target reel load <TB _{, n} > and the resulting reel load data TB _{, n} is calculated and output by the comparison circuit 45 each time. Then, the pressing of the lower reel disk 19 and the brake 7 is controlled according to the output target of the comparison circuit 45, and the error from the current target value of the drive current 49 is brought close to zero.

The tension detection by the capstan 10 will be described below with reference to FIG. An example is shown in which the capstan 10 is rotated by itself, the capstan 10 is pressed against the pinch roller 11, the capstan motor is rotated, and the tape 2 with the cassette tape 3 is driven. As shown in the figure, as the unit drive current of the capstan 10, the loss current of the capstan motor 10 and the motor drive circuit appears as a constant value unit current 47. Also, pinch rollers
The drive current of the capstan motor when 11 is loaded appears as pinch load current 48. Furthermore, during recording and playback,
If the tape 2 is being transferred, the tape drive current 49 that changes according to the transfer amount of the tape 2 from the supply reel 4 is added to the pinch load current 48 and appears as the load current 50. This tape drive current 49 is proportional to the tape tension. Load current 50
Is detected, the pinch load current 48, which is a constant load while the tape is running, is detected in advance, and the tape drive current 49 of the tape 2 is calculated by removing the pinch load current 48.

The calculation method of the target load torque <TB _{, n} > for each time will be described below with reference to FIGS. This corresponds to the process of three circuits of the tape tension calculation circuit 52, the reel load calculation circuit 51, and the comparison circuit 45 in the functional block diagram of the present embodiment of FIG. In FIG. 16, the recording / reproducing start time t
In _0, from the reel load calculating circuit 51, the initial target Reel load <T _{B, 0>} = Reel Weighted Average <T _B> outputs, simultaneously tape tension calculating circuit 52 from the target tension <T _c>
Is output and the set value of the comparison circuit 45 is set to 0. The initial target point <P ₀ > is a temporarily set target point. As shown in FIG. 17, the data point P ₀ has an error from the initial target point <P ₀ >. 17, the reel Weighted Average <T _B>
And the difference between the reel load data T _{B, 0 and} the difference between the target tension <T _c > and the tension data T _{c, 0} are _calculated .
Apply to. In Fig. 18, target reel load <T
The ratio of the difference between _{B, 1} > and the reel load data T _{B, 1 and} the difference between the target tension <T _{C, 1} > and the tension data T _{C, 1} is set equal to the above ratio. That is,

[0034]

[Equation 1]

It is assumed that Hereinafter, FIG. 19 at time t _n−1 ,
The relationship with FIG. 20 at time t _n is similar to the relationship between FIG. 17 and FIG.

[0036]

[Equation 2]

It is assumed that Transforming this formula, each time the target reel load is

[0038]

[Equation 3]

[0039] Here, each time the target tension <T _{C, n>} representing the tape tension is the target value to be kept constant, can be regarded as the target tension <T _C>. Therefore,

[0040]

[Equation 4]

By making the reel load data T _{B, n} approach the target reel load <T _{B, n} > each time, the tension data T _{C, n}
Performing tape tension control as a near not a Keru result target tension <T _C> the. Therefore, the output of the comparison circuit 45 is

[0042]

[Equation 5]

It is

The overall function of the sensor output shaping circuit 23 in this embodiment will be described below with reference to FIG. Reel load calculating circuit 51 in the recording and reproduction start time t _0, and outputs the reel Weighted Mean <T _B>. At time t ₁ after the time t _n, the output of the phase output 44 divided by the signal corresponding to the tape winding radius D / 2 determined from Makikei arithmetic circuit 42 outputs, reel load data T _B for the supply reel _4, Output _n . Tape tension operation circuit 52 outputs the target tension <T _C> In the recording playback start time t _0. Time t after time t _{1
At n} , the tape drive current 49 is calculated by inputting the load current 50 in the capstan 10, and the tension data T _{C, n}
Output as. The comparison circuit 45 sets the target tension <T _C > pre-stored in this circuit, the reel load data T _{B, n−1} calculated in the past and also stored in this circuit, and the target reel load <T _B >. _{, n-1} 〉 and tension data T _{c, n-1} ,
Using the currently input T _{C, n} , it is output as an error between the target reel load <T _{B, n} > and the reel load data T _{B, n shown in} FIG. The above is the description of the operation of the sensor output shaping circuit 23 having the functional difference between the present embodiment of the present invention and the above embodiment. In this embodiment, by adding the capstan motor 10 to the configuration and adding the tape driving force in real time,
The influence of the pressing force of the lower reel disk 19 and the brake 7 on the tape tension is measured by the capstan 10 in real time.
Therefore, changes in the frictional force between the tape 2 and the running guide member due to environmental changes such as temperature and humidity, changes in tape rigidity due to differences in the type of tape 2 and thickness between manufacturers, and changes in tape load such as damage to the tape during recording and reproduction. Since it is possible to control the tape tension corresponding to the above, it is possible to improve the performance and reliability of the tape tension control device.

[0045]

As described above, according to the present invention, since the tension control device can be constructed without using the tension pin and the tension arm, the tape transfer mechanism has a wider margin and a small device can be obtained. There is.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a tension control device according to a first embodiment of the present invention.

2 is a bottom exploded perspective view of the upper reel disc and the lower reel disc of FIG. 1. FIG.

3 is a cross-sectional perspective view of FIG.

4 is a vertical cross-sectional view of the supply reel disc of FIG.

5 is a bottom view of FIG. 4. FIG.

6 is a block diagram showing the functions of the apparatus of FIG. 1. FIG.

FIG. 7 is a waveform diagram showing a method for detecting a phase difference and a period when the load on the supply reel disk is large in the first embodiment.

FIG. 8 is a waveform diagram showing a method for detecting the phase difference and the cycle when the load on the supply reel disk is small in the first embodiment.

FIG. 9 is a side view and a bottom view of the supply reel disc according to the second embodiment when the load on the supply reel disc is large.

FIG. 10 is a side view and a bottom view of the supply reel disc according to the second embodiment when the load on the supply reel disc is small.

FIG. 11 is a detailed view of FIG. 9 and a side view in which the gap between the magnet and the lower magnet is small.

FIG. 12 is a detailed view of FIG. 10 and a side view showing a large gap between the upper magnet and the lower magnet.

FIG. 13 is an exploded perspective view showing a tension control device according to a third embodiment of the present invention.

14 is data showing a lapse of time of a load current of the capstan for explanation of FIG. 13. FIG.

FIG. 15 is a block diagram showing functions of the apparatus of FIG.

16 is a graph showing a setting method at the start of recording / reproducing in the block diagram of FIG.

17 is a graph showing a calculation method at the start of recording / reproduction in the block diagram of FIG.

18 is a graph showing a calculation method at time t ₁ in the block diagram of FIG.

FIG. 19 is a graph showing a calculation method at time t _n−1 in the block diagram of FIG.

20 is a graph showing a calculation method at time t _n in the block diagram of FIG.

FIG. 21 is a plan view showing a conventional example.

22 is a perspective view of FIG. 21. FIG.

23 is a partially exploded view of FIG.

[Explanation of symbols]

 2 Tape 4 Supply reel 7 Brake 10 Capstan 11 Pinch roller 18 Upper reel disc 19 Lower reel disc 20 Elastic member 21 Upper rotation sensor 22 Lower rotation sensor 30 Upper magnet 31 Lower magnet 42 Roll diameter calculation circuit 43 Target phase output Circuit 44 Phase output circuit 45 Comparison circuit 51 Reel load calculation circuit 52 Tape tension calculation circuit

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[Procedure amendment]

[Submission date] September 18, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

In FIG. 6, 42 is the output of the lower rotation sensor.
A winding diameter calculation circuit that calculates the tape winding diameter of the supply reel 4 from 33. 43 is a target phase output circuit that outputs a target phase difference corresponding to the magnitude of the output of the winding diameter calculation circuit 42.
Is a phase output circuit that outputs a phase difference 38 from the upper rotation sensor output 32 and the lower rotation sensor output 33, and 45 is an error signal obtained by comparing the output of the target phase output circuit 43 and the output of the phase output circuit 44. It is a comparison circuit that inputs to the actuator drive circuit.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

A method of detecting the cycle 39 of the supply reel 4 and the phase difference 38 between the upper reel disk 18 and the lower reel disk 19 will be described. The cycle of the supply reel 4 is calculated in the winding diameter calculation circuit 42 shown in FIG. 6, and the lower sensor pulse 37 indicates the time when the value of the lower rotation sensor output 33 becomes the threshold value 35 or more as a width. It can be obtained by detecting the interval at which the upper sensor pulse 38 is generated or the interval at which the upper sensor pulse 38 is generated, the interval being the width at which the value of the upper rotation sensor output 32 becomes the threshold value 34 or more.
7 and 8, the period 39 is shown as the interval at which the lower sensor pulse 37 is generated. The phase difference 38 between the upper reel disk 18 and the lower reel disk 19 is calculated in the phase output circuit 44, and the upper sensor pulse 36 and the lower sensor pulse
Detected as an interval with 37. 7 and 8, the phase difference 38 is shown by the time interval between the falling edge of the lower sensor pulse 37 and the falling edge of the upper sensor pulse. FIG. 7 shows a case where the load on the supply reel disc 19 is large, and the phase difference 38 is larger than that when the load on the supply reel disc 19 shown in FIG. 8 is small.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction content]

FIG. 15 shows the difference between this embodiment and the above embodiment in terms of function. Sensor output synthesis circuit in this embodiment
The inside of 23, the relationship between the sensor output combining circuit 23 and the capstan 10 is shown by a block diagram. In the figure, 51
Is a reel load calculation circuit that calculates and outputs the load of the brake 7 on the reel 4 using the output of the phase output circuit 44 and the output of the winding diameter calculation circuit 42. Reference numeral 52 is a tape tension calculation circuit for converting the tape drive current 49 from the load current 50 in the capstan 10 and calculating and outputting the tape tension. T _{C, n}
Is the output of the tape tension calculation circuit 52, and the subscript n is tension data indicating that it is the nth output data after the start of the recording / reproducing operation. T _{B, n-1} and T _{B, n} are outputs of the reel load calculation circuit 51, which are reel load data which are n−1 and n-th output data after the start of the recording / reproducing operation, respectively. <TB _{, n} > is the output of the comparison circuit 45, is also a target value for the reel load TB _{, n} , and is the target reel load data output for the nth time after the start of the recording / reproducing operation.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

In FIGS. 17 and 19, t = t ₀ , t = t _n-1.
Reel load data T _{B at, 0, T B, n-} 1, Tsutomu Cho data T
_{c, 0, T c, n} -1 and each time the target reel load <T _{B, n>,} indicating a relevant target tension <T _C>. 18 and 20, t = t
₁ , reel load data T _{B, 1} , T _{B, n} at t = t _n , tension data T _{C, 1} , T _{C, n} and target reel load for each time <
T _{B, 1} ＞, 〈T _{B, n} 〉 Each time target reel load 〈
T _{B, 1} >, <T _{B, n} > target tension calculated each time <T _{B, 1} >, <T _{B, n} > target tension calculated each time <T _{C, 1} >, <T _{C, n} >.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0044

[Correction method] Change

[Correction content]

The overall function of the sensor output synthesis circuit 23 in this embodiment will be described below with reference to FIG. Reel load calculating circuit 51 in the recording and reproduction start time t _0, and outputs the reel Weighted Mean <T _B>. At time t _n after time t ₁ , the output of the phase output circuit 44 is divided by the signal corresponding to the tape winding radius D / 2 obtained from the output of the winding diameter calculation circuit 42, and the reel load data T _B, Output _n . Tape tension operation circuit 52 outputs the target tension <T _C> In the recording playback start time t _0. Time t after time t _{1
At n} , the tape drive current 49 is calculated by inputting the load current 50 in the capstan 10, and the tension data T _{C, n}
Output as. The comparison circuit 45 sets the target tension <T _C > pre-stored in this circuit, the reel load data T _{B, n−1} calculated in the past and also stored in this circuit, and the target reel load <T _B >. _{, n-1} 〉 and tension data T _{c, n-1} ,
Using the currently input T _{C, n} , it is output as an error between the target reel load <T _{B, n} > and the reel load data T _{B, n shown in} FIG. The above is the description of the operation of the sensor output synthesizing circuit 23 having the functional difference between the present embodiment of the present invention and the above embodiment. In this embodiment, by adding the capstan motor 10 to the configuration and adding the tape driving force in real time,
The influence of the pressing force of the lower reel disk 19 and the brake 7 on the tape tension is measured by the capstan 10 in real time.
Therefore, changes in the frictional force between the tape 2 and the running guide member due to environmental changes such as temperature and humidity, changes in tape rigidity due to differences in the type of tape 2 and thickness between manufacturers, and changes in tape load such as damage to the tape during recording and reproduction. Prevent problems based on
Since the tape tension can be controlled correspondingly, the performance and reliability of the tape tension control device can be improved.

[Procedure Amendment 6]

[Document name to be corrected] Drawing

[Correction target item name] Figure 8

[Correction method] Change

[Correction content]

[Figure 8]

[Procedure Amendment 7]

[Document name to be corrected] Drawing

[Correction target item name] Figure 9

[Correction method] Change

[Correction content]

[Figure 9]

[Procedure Amendment 8]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 13

[Correction method] Change

[Correction content]

[Fig. 13]

Claims (3)

[Claims] 1. A supply reel disc comprising an upper reel disc that rotates integrally with a supply reel and a lower reel disc that is pressed by a brake, and an upper reel disc that detects and outputs the number of revolutions of each of the upper and lower reel discs. A lower rotation sensor, a phase output circuit that detects the phase difference between the outputs of the upper and lower rotation sensors, and a winding diameter calculation circuit that outputs the winding diameter of the supply reel from the output of the upper or lower rotation sensor, A target phase output circuit that receives the input of the winding diameter calculation circuit and outputs a target value to the phase output circuit, a comparison circuit that outputs an error between the phase output circuit and the output of the target phase output circuit, and this comparison A tape tension control device composed of an actuator that drives a brake by circuit output. 2. An upper magnet integrated with the upper reel disc and a lower magnet integral with the lower reel disc that receives a magnetic attraction force of the upper magnet. The tape tension control device described. 3. A capstan for detecting a load current at the time of recording / reproducing, a tape tension calculation circuit for outputting tape tension data corresponding to the tape tension obtained from the load current, an output of the phase output circuit and the winding. A reel load calculation circuit that outputs reel load data indicating the load load on the supply reel from the output of the diameter calculation circuit, a target value of reel load data that matches the tape tension data with a target value, and the current reel load data. 2. The tape tension control device according to claim 1, further comprising a comparison circuit for calculating and outputting the error.