JPS61168167A - Tape driving controller - Google Patents

Abstract

PURPOSE:To stabilize the loading of a tape and to obtain a controller suitable to integration by detecting the rotational quantity of a payoff side reel as the tape is loaded and controlling a payoff side reel motor so that the back tension generation torque of the tape is decreased according to the detection output. CONSTITUTION:A take-up side reel turntable 13 is fixed by a brake 18 in tape loading and the tape wound around the payoff side reel 5 is unwound by a loading post 11 to rotate to the payoff side reel turntable 12. Rotation information on its is detected by a reel FG23, whose output signal is counted by a counter 19; and the output of a correcting torque generating circuit 22 is increased according to the counted value and subtracted by a subtracted 22 from the output of a payoff side torque generating circuit 21 and the result is applied to a payoff side motor driving circuit 14, so that torque is generated in the back tension direction of the tape by the payoff side reel motor 7. Therefore, the tape tension is weakened in the latter half period of the loading and the tension at the exit of the payoff side reel is controlled to a constant value.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a tape drive control device suitable for stabilizing tape running during loading of a VTR, for example.

2. Description of the Related Art Conventionally, this type of tape drive control device has had a configuration as shown in FIG. FIG. 2 shows a block diagram of a conventional example of the configuration of a tape running system of a cassette type video tape recorder (hereinafter referred to as a VTR) and tape loading of a tape drive control device. In FIG. 1, 1 indicates the tape force cent, and 2 indicates the magnetic tape. 3 and 4 are VT
Each reel shaft on the supply side 9 winding side of the tape cassette R is adapted to engage with each reel 5, 6 on the supply side 9 winding side and each reel stand 12, 13 of the tape cassette 1. 7
, 8 are respective reel motors on the supply side 9 and on the winding side which directly drive the respective reel shafts 3 and 4 on the supply side and the winding side.

Reference numeral 9 denotes a rotary head cylinder in which a pair of rotary video heads is provided. The tape 2 is pulled out from inside the tape cassette 1 through the rotation post 11, is wound around the 3"-rotating head cylinder 9 at an angle of about 1800 degrees, and is wound at a predetermined speed by the capstan shaft 1o. Transfer it with b.

When loading a tape, the output of the supply side torque generation circuit 16 is input to the supply side motor drive circuit 14 to cause the supply side reel motor 7 to generate a predetermined torque, and
By inputting the output of the take-up side torque generation circuit 17 to the take-up side motor drive circuit 15 and causing the take-up side reel motor 8 to generate a predetermined torque, tension is generated in the tape to prevent the tape from falling off during loading. It was to prevent it.

Problems to be Solved by the Invention In such a conventional configuration, a constant current (Is ), the generated torque (ΦS) of the supply side reel motor 7 is determined by the torque generation constant (KTs) of the supply side reel motor 7.
- (1) The tape tension (Ts) at the exit from the supply reel is determined by the winding diameter (R8) of the tape wound on the supply reel: Ts - Φs/R8... ...(2), and since the torque ΦS generated by the supply reel motor 7 is constant, the tape tension (Ts
) is the radius of the magnetic tape wound on the supply reel (
The tape tension increases in inverse proportion to the decrease in R8), and as it passes through each post, the tape tension increases by eμθ (μ: tape friction coefficient, θ: tape winding angle), and the tape tension (TLl) increases at the loading post entrance. is giving.

Similarly, the reel motor 8 on the winding side also has a constant current (IT).
, the torque generated by the take-up reel motor 8 (ΦT) is equal to the torque generation constant (K) of the take-up reel motor 8.
TT), ΦT"KTT"IT °゛°°" (3) and the tape tension at the entrance to the take-up reel (TT)
is the radius (RT) of the tape wound on the take-up reel
Then 5 ・＼− TT=ΦT/RT −・−・・・・・・・
...(4), and since the torque generated by the take-up reel motor 8 (ΦT) is constant, the tape tension (Ts) at the entrance to the take-up reel is wound around the take-up reel. The tape tension increases in inverse proportion to the decrease in the radius (RT) of the magnetic tape, and as it passes through each post, the tape tension increases, providing tape tension (TL2) at the entrance of the loading post. Therefore, the tape tension (TL) near the loading post TL = TL1 + TL2
(6) has the problem that it varies depending on the radius of the magnetic tape wound on the reel, making it impossible to obtain tape tension suitable for loading.

The present invention is intended to solve these problems, and aims to provide a tape drive control device that stabilizes tape loading and is suitable for integrated circuit implementation.

Means for Solving the Problem In order to solve this problem, the present invention provides a system for detecting the rotation amount of the take-up side reel stand and the supply side reel stand, which are braked during tape loading. It consists of a detection means and a servo circuit for the supply side reel motor.

(With this configuration), at the beginning of loading, the supply reel motor generates a constant torque, and as the tape is loaded, the rotation amount of the supply reel is detected.
Stable tape loading can be achieved by reducing the torque generated by the supply reel motor that generates tape back tension in accordance with the output of the rotation amount detection means and generating tape tension suitable for loading.

Embodiment FIG. 1 is a block diagram of a tape drive control device according to an embodiment of the present invention. In FIG. 1, during tape loading, the take-up side reel stand 13 is fixed by the brake 18 and the supply side is fixed by the loading post 11. The tape wound around the reel 6 is pulled out and the supply side reel stand 12 is rotated. This rotation amount information of the reel stand is detected by the reel FG23, and the output signal is counted by the counter 19, and the output of the correction torque generation circuit 2o is increased according to the count value, and the supply side torque is generated. The output of the circuit 21 is combined with the subtracter 22 and applied to the supply side motor drive circuit 14, and the supply side reel motor generates a torque in the back tension direction of the tape.

According to the configuration of the embodiment of the present invention as described above, the amount of tape drawn out by loading is constant n1 [Q], the number of FG teeth ZR [pieces], the number of FG counts NR [pieces], and the number of tapes wound on the reel is radius R8 (111111
:] then holds true.

At the beginning of loading, depending on the output of the supply side torque generation circuit 21, the supply side reel motor maintains a constant torque Φs.
1 is generated in the back tension direction.

As the loading progresses, the subtracter 21 subtracts the output produced by the correction torque generation circuit 21 according to the FG count number NR from the initial torque.

As a result, the tape tension (T3) at the exit from the supply reel is here Φ52 (NR) is a correction torque according to the FG count number NR.

From equations (6) and (7), when the tape winding diameter of the supply side reel stand is large, the tension at the initial stage of loading is small, so the correction amount (the second term on the right side of equation (7)) is also small. In addition, if the tape winding diameter of the supply side reel stand is small, the tension at the beginning of loading will be large, but in the latter half of loading when the winding angle θ with the loading post becomes large, the amount of tortion correction will increase and the tape tension will increase. can be controlled so that the tape tension (CTS) at the exit of the supply reel is kept approximately constant.

Effects of the Invention As described above, according to the present invention, when loading a tape, back tension is generated by constant torque without malfunction in the early stage of loading, and torque correction is performed in the latter half of loading when abnormal tension is likely to occur. Tape tension can be easily and appropriately controlled.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a tape drive control device according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional tape drive control device for a cassette type VTR. DESCRIPTION OF SYMBOLS 1... Tape cassette, 2... Magnetic tape, 3... Supply side reel shaft, 4-... Winding side reel axis, 6... Supply side reel, 6 ...Take-up side reel, 7... Supply side reel motor, 8... Take-up side reel motor, 9... Rotating head cylinder,
1o... Capstan shaft, 11-- Loading post, 12... Supply side reel stand, 13-...
・Take-up side reel stand, 14...supply side motor drive circuit, 15...-take-up side motor 10 parts・

Claims (2)

[Claims] (1) Of a pair of reel stands, a take-up reel stand to which a brake is applied, a rotation amount detection means for detecting the amount of rotation of the supply reel stand, and a servo circuit for the supply reel motor; A tape drive control device characterized in that, while applying a brake on a side reel stand, torque generated by a supply side reel motor that generates tape back tension is reduced in accordance with the output of the rotation amount detection means. (2) The back tension generation torque of the supply reel motor is divided into a constant torque regardless of the rotation amount of the reel stand and a portion that decreases depending on the rotation amount, so that the back tension generation torque is adjusted according to the rotation amount of the supply side reel stand. The tape drive control device according to claim 1, characterized in that the tension generating torque is reduced.