JPH04321987A - Device for measuring diameter of wound tape - Google Patents

Abstract

PURPOSE:To provide device with which the diameter of a wound tape is accurately measured. CONSTITUTION:In the device for measuring the diameter of the wound tape in a tape travelling mechanism in which a tape wound up on a supplying reel 11 is forwarded to a take-up reel 12 by means of a prescribed travelling mechanism, travelling in the forwarding direction in which the tape is wound up on the take-up reel and travelling in the reverse direction in which the tape is wound up on the supplying reel are performed, and by using the measured values of the traveling in both directions, the measurement of the accurate diameter of the wound tape is facilitated.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape winding diameter measuring device suitable for measuring the winding diameter of a reel of a VTR (video tape recorder).

0002

2. Description of the Related Art When running a tape in a VTR or the like, torque is applied to a tape supply reel and a take-up reel to apply a predetermined tension to the tape.

By the way, if the torque applied to the supply side and take-up side reels is constant, the tension will change depending on the tape winding diameter of each reel, and the tension will be weaker on the tape with a smaller winding diameter, causing the tape to loosen. However, the tape with a larger diameter has the disadvantage that the tension is too strong, causing damage to the tape.

Conventionally, therefore, the tape winding diameters of the supply and take-up reels are detected, and the torque to be applied to each reel is determined in accordance with the detected tape winding diameters.

[0005]Alternatively, even when the tape is run at high speed, if the tape reaches the end or top of the tape while running at high speed, the tape may be damaged. is detected, and control is performed to slow down the tape speed when near the tape end or tape top.

[0006] In these cases, the following method is available for measuring the tape winding diameter (Japanese Patent Laid-Open No. 63-23
(See Publication No. 4433). That is, first, the capstan FG (
The amount of tape travel is determined by counting the output pulses of the frequency generator), and the supply reel FG at that amount of tape travel,
The rotation angle of each reel is determined by counting the output pulses of the take-up reel FG, and from the relationship of rotation angle x radius = tape running distance, the tape winding diameter RS (radius, the same applies hereinafter) of the supply reel at that time and Determine the tape winding diameter RT (radius, same hereinafter) of each reel on the take-up side, and determine the total amount of tape (sum of area) A from the following formula.

[0007]

[Formula 1] πRS + πRT = A

After the total tape amount A has been determined, the output pulses of the supply reel FG and take-up reel FG are counted while the tape is running, and the tape winding diameters RS and RT are determined by the ratio NS /NT of the count values. RatioRS/RT
=(NS/NT)-1 and calculates each tape winding diameter RS and RT from the formula [Equation 1].

[0009]

[Problems to be Solved by the Invention] However, such measurement of the tape winding diameter has the disadvantage that accurate measurement is difficult and errors occur in the measured values. In other words, due to vibrations of the capstan or slippage of the tape, the output pulse of the capstan FG may not be accurately proportional to the amount of tape travel, and similarly, errors tend to occur in the measured value of the reel rotation speed, resulting in poor measurement. Errors often occurred in the values.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a tape winding diameter measuring device that can accurately measure the tape winding diameter.

[0011]

[Means for Solving the Problems] The present invention provides, for example, as shown in FIG.
In a tape winding diameter measuring device of a tape running device that sends the tape to the take-up reel 12 via a predetermined running mechanism and winds it up on the take-up reel 12, the tape winding diameter measuring device is configured to transport the tape to the take-up reel 12 via a predetermined running mechanism and to take it up on the take-up reel 12. The coil is wound on the side reel 11 and runs in the opposite direction, and the measured values obtained by running in both directions are determined to measure the winding diameter.

0012

[Effect] By doing this, when the measured values obtained by driving in both directions are the same, it can be determined that accurate measurements have been made, and even if the measured values obtained by driving in both directions are different, the measured values obtained by driving in both directions are By using the one with the least error, more accurate measurements with fewer errors can be made.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a measuring device according to the present invention, and this example is applied to a video tape running mechanism of a VTR. It is a take reel. Further, 13 is a motor for driving the supply reel 11, and 14 is a motor for driving the take-up reel 12.

15A, 15B and 16A, 16B are loading pins, and 17 is a rotating head drum. Also,
18 is a loading motor, loading drive gear 1
9 is driven by this motor 18.

Further, 21 indicates a capstan, and 22
is the drive motor for the capstan 21, and the motor 22
The capstan 21 controls the running speed of the tape.

Reference numeral 20 denotes a microcomputer (hereinafter abbreviated as microcomputer) for controlling tape running, and this microcomputer 20 is supplied with signals from a frequency generator 13H attached to the supply reel drive motor 13. , information indicating the frequency and direction of rotation of the motor 13, and therefore of the reel 11, is given to the microcomputer 20. Similarly, the signal from the frequency generator 14H attached to the take-up reel drive motor 14 is transmitted to the microcomputer 2.
0, and the microcomputer 20 is provided with information indicating the frequency and rotational direction of the motor 14, and hence the rotational speed of the reel 12. Furthermore, a signal from a frequency generator 22H attached to the capstan drive motor 22 is supplied to the microcomputer 20, and the frequency and frequency are determined according to the rotation speed of the capstan 21 which is proportional to the running speed of the motor 22 and therefore the tape. Information indicating the direction of rotation (direction of travel) is given to the microcomputer 20.

A torque control signal for the supply reel motor 13 and a torque control signal for the take-up reel motor 14 are obtained from the microcomputer 20 and supplied to these motors 13 and 14. Further, a loading drive signal is supplied to the loading motor 18. Furthermore, a speed control signal is supplied to the capstan motor 22.

Next, the control by the microcomputer 20 of the tape running system constructed in this way will be explained with reference to the flowchart shown in FIG.

First, when the tape cassette 10 is inserted into the VTR and the tape is loaded onto the rotating head drum 17, the microcomputer 20 sets the number of measurements N to "0" and starts tape running in the forward direction (hereinafter referred to as FWD direction). The value indicating the judgment state of tape running (referred to as running) and the value indicating the judgment state of tape running in the opposite direction (referred to as
A value indicating the determination state of the vehicle (hereinafter referred to as REV direction traveling) is set to "0" (step 101). And then,
Determine whether the number of measurements N is less than 5 (step 102)
, the following measurement is started when the number of times is less than 5 times. For this measurement, first, the tape is run a predetermined distance in the FWD direction, and the winding diameter is measured (step 103). The measurement at this time is performed based on the above-mentioned formula [Equation 1]. That is, the microcomputer 20 counts the output pulses of the frequency generator 22H on the capstan 21 side at this time to obtain the tape running distance, and also calculates the frequency generator 13H on the supply reel 11 side and the frequency generator 13H on the take-up reel 12 side. The rotation angle of each reel is determined by counting the output pulses of the machine 14H, and the tape winding diameter RS of the supply side reel and the tape winding diameter of the take-up reel at that time are determined from the relationship of rotation angle x radius = tape running distance. Calculate RT.

During the measurement in the FWD direction, it is determined whether or not the end of the tape has been reached (step 104), and when the end of the tape has been reached, the measurement in the REV direction is started. In this case, the amount of tape travel during measurement in the REV direction is set to 1.5 times the normal amount (step 105). When the measurement in the FWD direction ends before the end of the tape is reached (step 106), the value indicating the determination state in the FWD direction is set to "1" (step 107).

Next, the tape is run a predetermined distance in the REV direction to measure the winding diameter (step 108). The measurement at this time is also based on the above-mentioned formula [Equation 1].
It is done in the same way as for direction.

Then, it is determined whether or not the tape top has been reached during this measurement in the REV direction (step 109), and when the tape top has been reached, the tape traveling amount for the next measurement in the FWD direction is changed from the normal time. 1.5 times (step 110). Then, before the end of the tape, the REV
When the direction measurement is completed (step 111), R
It is determined whether the measurement in the EV direction has been performed stably (step 112), and when it is determined that the measurement has been performed stably, the RE
The value indicating the judgment state in the V direction is set to “1” (Step 1
13).

Then, it is determined whether or not the value indicating the determination status of both FWD and REV is "1" (step 114).
) and both are "1", it is determined whether the measured values in both directions are the same (step 115). Then, when the measured values in both directions are the same, this measured value is determined to be the correct measured value.

Furthermore, if the measured values in both directions are different in step 115, a warning message is displayed on the display section (not shown) of the VTR, and the maximum speed for subsequent tape running is set to a predetermined value slower than normal. limit (step 116). At this time, the value measured by running the tape in the REV direction is set as the winding diameter value (step 11).
7).

Further, when it is determined in step 112 that the measurement is not stable, or when the value indicating the determined state is not "1" in step 114, "1" is added to the number of measurements N. Then, the process is repeated starting from the determination of the number of measurements N in step 102.

[0027] Then, in the judgment of the number of measurements N in step 102, when it is detected that the number of measurements N has become 5 (that is, when good measurements could not be made after 4 measurements), the VTR Display on the display section that measurement is not possible (step 119), and stop the operation of the VTR (step 120).
).

In this example, by measuring the winding diameter in this manner, the winding diameter can be measured accurately with little error. That is, the running of the tape in the FWD direction and the RE
When running in the V direction, the load applied to the tape varies depending on the arrangement of the rotating head drum, tape guide, tension regulator, etc., and measurements were taken under different load conditions.
The value of each type of winding diameter is obtained. Here, if the values of the two types of winding diameters are the same, it can be determined that there was no tape slip during the measurement and accurate measurement was achieved. In addition, when the two types of winding diameter values are different, the value measured under the smaller load (in this example, tape running in the opposite direction) is determined to be the more accurate winding diameter measurement value, so the one with the least error is determined to be the more accurate winding diameter measurement value. is selected as the winding diameter value. Further, if the measurement cannot be performed correctly, it can be determined that there is some kind of abnormality in the tape drive mechanism, and the state of the drive mechanism can be determined.

[0029] By being able to more accurately determine the reel diameter value in this way, for example, when running the tape at high speed without using a capstan, the deceleration near the tape end (or tape top) can be controlled at the correct timing. This can be done at the tape end (
(or tape top) and damage the tape. Alternatively, even when determining the torque to be applied to each reel according to the detected tape winding diameter, the torque can be determined satisfactorily, and accidents causing damage to the tape can also be prevented from this point of view.

[0030]

According to the present invention, when the measured values obtained by traveling in both directions are the same, it can be determined that accurate measurement has been made, and even if the measured values obtained by traveling in both directions are different, the measured values obtained by traveling in both directions can be By using the one with less error, it is possible to perform accurate measurements with fewer errors, and in any case, it works to reduce measurement errors and allows for better operation control with accurate measurement values. become.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart diagram for explaining one embodiment.

[Explanation of symbols]

11 Supply reel 12 Take-up reel 13H, 14H frequency generator 20 Microcomputer 21 Capstan 22H frequency generator

Claims (1)

[Claims] [Claim 1] A tape wound on a supply reel,
In a tape winding diameter measuring device of a tape running device that sends the tape to a take-up reel via a predetermined running mechanism and winds it up on the take-up reel, the tape winding diameter measuring device is configured to transport the tape to the take-up reel through a predetermined running mechanism and to take it up on the take-up reel. A tape winding diameter measuring device that measures the winding diameter by winding the tape onto a side reel and traveling in the opposite direction, and determining the measured values obtained by traveling in both directions.