JPS5828668B2 - Tape amount display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an apparatus for winding a tape of a constant thickness from a supply reel to a take-up reel and rewinding it in the opposite direction, such as a tape recorder or a VTR. This invention relates to a tape amount display device that digitally displays the amount of tape wound up to a certain point or the amount of tape remaining on the supply reel.

Conventionally, tape amount display devices for tape recorders and the like include a method of recording cue signals on a tape in advance and counting the cue signals, or a method of counting and displaying the number of turns on a reel.

However, the former method has the inconvenience of having to record a cue signal on the tape in advance, and also has the inconvenience of not being able to determine the amount of tape from the beginning of winding if the tape is used from any position on the tape. Ta.

Furthermore, in the latter method, since the winding diameter of the tape is involved in this case, there is no unambiguous correspondence between the reel rotation speed and the amount of tape used, making it impossible to determine the exact amount of tape used.

The present invention does not require the trouble of recording signals on the tape in advance, and can be applied to the take-up reel at any time, even when changing the tape from any position, or even during fast forwarding or rewinding. It is an object of the present invention to provide a tape amount display device that can digitally display the amount of tape wound up and the amount of tape remaining on the supply reel in terms of time.

A feature of the present invention is that the time required for the take-up tape to go around the circumference or the time required for moving one portion of the circumference divided into multiple equal parts is measured at any point in time, and a linear function of this measured time is obtained. Find the number of tape turns on the take-up side tape at the arbitrary time point mentioned above, and calculate the tape use time until the above number of turns is reached, or the tape remaining amount time until the remaining amount of tape is used up, as a quadratic function of this number of tape turns. The purpose is to adopt a configuration that performs calculations and displays them using a circuit.

The present invention will be explained below with reference to the drawings.

This will be explained using a tape recorder as an example.

FIG. 1 shows a top view of a tape recorder, in which a tape having a certain thickness D is passed through a head 3 at a constant speed 2 on a take-up reel 1.

2 is a supply reel, 4 is a capstan, 5 is a pinch roller, and 6 is a guide roller.

In this case, there is a relationship between the winding radius r of the tape on the take-up reel 1 and the number of turns n of the tape assuming that the bubble radius R1 of the reel is zero.

On the other hand, when the rotation radius of the take-up reel 1 is r, the period, that is, the time required for the tape to go around the circumference, is expressed as t.

In other words, there is a linear proportional relationship between the time t- required for the tape to go around the circumference of the take-up reel at any point in time and the number of tape turns n at the same point in time, which can be expressed using a graph. The diagram is shown in Figure 2.

In FIG. 2, the horizontal axis represents the number of tape turns n, and the vertical axis represents the time required for the tape to wrap around the circumference.

However, the number of tape turns n is the number of turns when the bubble radius R1 is considered zero, and the actual number of turns wound on the bubble radius is the second
It is obtained by subtracting the number of tape turns at point a, number No. B-1, from the number of tape turns n in the figure.

Here, T. represents the area of triangle Oah, and is the virtual tape use time until the winding radius r of the tape reaches the bubble radius R1 of the take-up reel, which is expressed as follows.

Next, consider the minute portion where the tape wound on the reel passes through an arbitrary number of turns N, based on FIG. 2-1.

In other words, consider the time Atn required for the number of tape turns to increase from N-i to N.

However, K is a division constant that equally divides the circumference at the number N of tape turns.

At this time, Ato. is the trapezoid cdef in Figure 2-1
is the area of , and is expressed as follows.

Similarly, Jtn, denotes the area of trapezoid bcfg, which is defined by the number of turns of tape from N2 to N1.
This is the time required for R rotation of KK and is expressed as follows.

From equations (4) and (5), Also, When formula (4) is rearranged with respect to N, becomes.

Equation (7) is expressed as follows: tape winding speed is ■, tape thickness is D, time required for the winding tape to move one division of the circumference at any given point, (1 This shows that the number of tape turns N can be found as a linear function of .

Also, in equation (7), assuming K=1, then jJ
If tn is Jpn, that is, if the time required for the tape to go around the same circle is Jpn, equation (7) becomes as follows.

Furthermore, from equations (4) and (6), it can be rewritten as follows, and tape speed ■ and tape thickness D
The formula for displaying the number of tape turns N does not include .

When the number of tape turns N is defined as shown in Figure 2-2, the area Atn of trapezoid b'c'f'l and trapezoid c'd'
Letting the area of e'f' be Jt, a relational expression based on the same n+1 concept as above can be obtained.

Equations (7'), (8'), and (9') are relational expressions used when measuring by rotating the take-up reel 1 in the opposite direction.

If the area of the trapezoid a'b'g'11' in the second section of the trapezoids ade, h, and g2 in FIG. 2-1 is T, then this is the tape usage time until the number of turns reaches N.

Equation (10) indicates that the tape usage time T up to an arbitrary point in time can be determined as a quadratic function of the number of tape turns N at that arbitrary point in time.

Furthermore, as stated in equations (8), (8') and (7), (7'), the number of tape turns N is the time Jpo required for the tape to go around the circumference at any given point, or the circumference Since it can be determined as a linear function of the time Jtn required to move one divided portion of It can be calculated by measuring the time Jpn or the time Jto required to move one portion of the circumference divided into equal parts.

If the tape usage time T up to an arbitrary point in time is determined as described above, the tape remaining amount time TR can be determined as follows.

However, TA is the total tape usage time, and L is the total length of the tape.

Figure 3 shows the relationship between the number of tape turns N and tape usage time T in equation (10) and the relationship between the number of tape turns N and remaining tape time TR in equation (11), with the number of tape turns N on the horizontal axis. This is a graph.

In the present invention, the relationship between the time Apn required for the tape to go around the circumference at any given point, or the time Atn required for moving one portion of the circumference divided into equal parts, and the number of tape turns N is a linear function. By using the fact that the relationship between the tape usage time T and the number of tape turns N is a quadratic function, the time required for the tape on the take-up reel to rotate upward on its circumference, Jt
By detecting K n and comparing this with the time of the reference signal to accurately measure Atn, substituting this into equation (7), and substituting the calculated number of tape turns N into equation (10). Retape usage time T
This is what we are trying to find.

An embodiment of the present invention will be described with reference to FIGS. 4 and 5.

FIG. 4 shows a block diagram of a detecting section, and FIG. 5 shows a block diagram of an embodiment of the apparatus which calculates and displays the tape usage time T based on a signal from the detecting section.

In FIG. 4, 7 is a disk integrally attached to the take-up reel (1 in FIG. 1), and slits are formed at positions that equally divide the circumference of the disk.

The reason why two slits are provided at the same position and out of phase is that the direction of rotation of the reel can also be detected.

8a and 8b are light emitting diodes, and 9a19b is a phototransistor fixedly arranged with the disk 7 in between so as to correspond to the light emitting diodes 8a and 8b, respectively.

Each time the take-up reel rotates, the phototransistor 9
A number of pulses are generated from a19b.

Reference numeral 10 in FIG. 5 is a rotation direction detector composed of a waveform shaping circuit 10a, a differential circuit 10b, and a waveform shaping circuit 10c in FIG.
.

, a reverse rotation pulse Re1 and a common pulse M are generated.

When the take-up reel is rotated in a forward rotation constant speed feeding state, a forward rotation pulse F is generated as shown in FIG.

The pulse interval becomes the time Jtn required for K rotation.

Therefore F.

The gate control signal G is generated from the gate control signal generator 11 by
By generating and applying to the gate circuit 13 together with the output S of the reference signal generator 12, the X/
Since a pulse corresponding to the rotation time Jtn is obtained, the rotation time Jtn can be obtained by inputting it to the period measuring circuit 14.

The rotation time Jtn is determined by the calculation circuit 1 based on equation (7).
7 to obtain the number of tape turns N, which is input to an adder/subtracter 18 having a memory function.

After the tape winding number N is stored in the adder/subtractor 18 having a storage function, its contents are the signal F from the rotation direction detector 10.

, increases or decreases depending on Re. That is, the forward rotation pulse F.

When is input, K is divided by addition, and when reverse rotation pulse Re is input, K is subtracted.

The tape usage time T can be calculated by processing the output of the adder/subtractor 18 having a memory function in the arithmetic circuit 19 based on equation (10).

What is determined here is the time in seconds, so this is divided by 60 in the division circuit 21 to determine the time in minutes, and the tape is displayed on the digital display 23 through the display circuit 22 using, for example, an LED element. Display the time corresponding to usage.

Note that 24 in FIG. 5 is a constant P0 used in the arithmetic circuit 17.
,P! and a constant P3 used in the arithmetic circuit 19. As mentioned above, the embodiment in FIG. 5 is a case where the tape thickness D is clearly known, and N=P −Jtn+
Constants P1, P2- of the formula P2 and T-P2H4-P4
5, P3, and P4 are set in advance in the memory circuit 24 and the calculation process is performed.Next, the process when the tape thickness D is not clear will be explained with reference to FIG.

The difference between Figure 6 and Figure 5 is The difference is that a subtraction circuit 15 is added to calculate .

In Fig. 5, 15 is a period measuring device that measures only Atn, but in Fig. 6, the period measuring device 14 has 1t.
Measure n-1 and Atn.

Enter the measured Atn-1 and Atn into the subtraction circuit 15,
Here, X in equation (6') is calculated, and the obtained X is input into the memory circuit 24 to obtain a constant.

By proceeding with the subsequent calculation process in exactly the same manner as in the case of FIG. 5, it is possible to display the chi usage time T on the digital display 23 without using the tape thickness D.

Next, FIG. 7 shows an embodiment in which the remaining tape time TR is calculated.

The difference between FIG. 7 and FIG. 5 is that in FIG. 7, in addition to the four constants P, ~P4, the total tape usage time TA is preset in the memory circuit 23. In addition, in place of the arithmetic circuit 19, an arithmetic circuit 20 for calculating is installed.

The rest is the same as the embodiment shown in FIG. 5, and therefore the operation in FIG. 7 can be more easily analogized than in the case shown in FIG. 5, so redundant explanation will be avoided.

FIG. 8 shows an embodiment designed to allow accurate display even when reverse rotation is performed when measuring the rotation time Jtn on the winding side.

The difference between FIG. 8 and FIG. 5 is that the input of the gate control signal generator 11 is taken from the common pulse output M of the rotation direction detector 10, and that the constant in the arithmetic circuit 17 is determined by the forward/reverse rotation determiner 16. This is to switch the sign of P2.

Since the operation shown in FIG. 8 can be easily inferred, redundant explanation will be avoided.

In the embodiment device having the above configuration, the time required for the tape on the take-up reel to rotate around its circumference at any given point corresponds to the tape winding amount, that is, the tape time amount, and the tape Since processing is performed in a state where the number of tape windings is converted to N, even in fast forwarding or rewinding states, the time display follows the tape winding amount in the same way as during normal feeding.

Additionally, if the hub radius R1 of the take-up reel is changed, the start position of the wound tape can be set to zero by changing the setting of constant P4, which is related to R1. This also makes it possible to count true usable tapes, excluding leader tapes.

In addition, by preparing and storing a larger number of constants P□ to P4 set in the memory circuit 24, it is possible to correspond to various types of tapes and many types of hub diameters by simply switching the output. The device can be used in a wide range of applications.

In the above embodiment, the period P or the upper rotation time n
K Jt, was measured, and based on this, the number of turns N and tape usage time T were calculated.
It is also possible to obtain

FIG. 9 shows the block configuration countries in that case. The difference between FIG. 9 and FIG. 8 is that the gate circuit 13 obtains a signal (see time chart) proportional to the rotation speed S
The purpose is to obtain Jtn according to the above relational expression Jt =Sn, and to obtain the output pulse corresponding to K in the apparatus shown in FIG. 8 by providing the frequency dividing circuit 25.

As described above, according to the present invention, by measuring the tape cycle at any time or the time required for the tape to rotate upward, it is possible to determine the amount of tape used or the remaining amount of tape at any time. In addition, the tape start position can be set simply by changing the constant settings of the memory circuit, and furthermore, by setting the constants of the memory circuit, it is easy to create a device with wide compatibility with tape types and reel types. There are some possible effects.

[Brief explanation of drawings]

Figure 1 is a top view of the tape recorder, Figure 2 is a diagram showing the relationship between the number of tape turns and cycle, Figure 3 is a diagram showing the relationship between the number of tape turns, tape usage time and remaining tape time, Figure 4 Figures 5 and 6 are examples of the detection unit of the tape amount display device.
7, 8, and 9 are block diagrams showing embodiments of the present invention, respectively. Explanation of symbols, 1... Winding side reel, 2...
... Supply side reel, 8a, 8b... Light emitting diode, 9a. 9b...Phototransistor, 10...
・Rotation direction detector, 11... Gate control signal generator, 12... Reference signal generator, 13...
...Gate circuit, 14...Period measurement circuit, 15
...Subtraction circuit, 16... Forward/reverse rotation discriminator, 17, 19, 20, 21... Arithmetic circuit, 1
8... Addition/subtraction device with memory function, 22...
...Display circuit, 23...Digital display,
24...Constant memory circuit.

Claims (1)

[Claims] 1. In a device that winds a tape of a constant thickness from a supply reel to a take-up reel and unwinds it in the opposite direction,
Measure the time required for the take-up tape to go around the circumference at any given point, or the time required to move one divided portion of the circumference divided into multiple equal parts, and calculate the time required for the take-up tape at any given time as a linear function of this measurement time. The number of tape windings on the take-up side is determined, and the tape use time until the number of windings is reached or the remaining amount of tape is determined and displayed as a quadratic function of this number of tape windings. Tape amount display device. 2 The tape winding speed is ■, the tape thickness is D, and the time required for the winding tape to go around the circumference at any given point is Ap.
2. The tape amount display device according to claim 1, wherein the number of tape turns N is determined by using 0 as the -order function. 3 Let the tape winding speed be ■, the tape thickness be D1, and the time required for the winding tape to move one division of the circumference at an arbitrary point, Atn, using the above-mentioned -order function. 2. The tape amount display device according to claim 1, wherein the tape amount display device calculates the number N of tape turns. 4. The time required for the take-up tape to move each of two consecutive parts of the circumference equally divided into two at any given point is Atn and "n+:1 s" n -1, and the above-mentioned -order function is used. 2. The tape amount display device according to claim 1, wherein the tape amount display device calculates the number of tape turns N by using the following steps. 5. A patent claim characterized in that the tape winding speed is ■, the tape thickness is D, the hub radius of the winding reel is R1, and the number of tape turns is N, and the tape usage time T is determined using as the quadratic function. The tape amount display device according to item 1. 6 A patent characterized in that the tape winding speed is ■, the total length is L1, the thickness is D1, the winding side tape hub radius is Ro, and the number of tape turns is N, and the tape remaining time TR is determined using as the quadratic function. A tape amount display device according to claim 1. 7 In the device set forth in claim 3, the time Jtn required for the winding side tape to move one divided portion of the same amount divided into equal parts is the time Jtn required for the winding side tape to move a portion of the circumference Measure the rotational speed Sn at the time of rotation, and use Jt = -', which is obtained as the reciprocal of this value. A tape amount display device featuring