JPS6126145B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tape tension control technique used in a tape winding device, etc., and an object of the present invention is to provide a tape tension control method that can set the tape tension to an arbitrary variation pattern.

FIG. 1 shows a schematic configuration of a tape winding device that uses a conventional air column to control tape tension. The tape 1 is supplied at a constant speed from a raw material reel 2, and tape running guides 3a, 3
b, 3c, etc., passes through a processing section 4 such as cutting and joining, and is wound onto a take-up reel 5. Reference numeral 6 denotes an air column which has the function of applying a constant tension to the tape and buffering sudden fluctuations in tape running. The air is exhausted by an air suction source 9. The tape 1 forms a loop 10 within the column, dividing the space within the column into an atmospheric pressure area 11 and a negative pressure area 1.
The tape 1 is divided into two parts, and a constant tension is generated in the tape 1 according to the differential pressure. Further, 13 is a device for detecting the position of the tip of the tape loop in the column, and by feeding back the detected signal to the take-up motor which is the drive source of the take-up reel 5, the position of the tape loop is determined as follows. It is controlled to a certain set position.

Generally speaking, when a tape-like object such as a magnetic tape is wound onto a take-up reel under constant tension, the tape winding tension is equal to the thickness of the tape layer relative to the already wound tape layer. It acts as a compressive force in the direction, and as a force that causes slippage between each layer of the tape. Therefore, if this winding tension is large, the tape on the take-up reel will tighten, causing scratches, push marks, wrinkles, folds, etc. on the tape, and in the case of magnetic recording tape, the magnetic head This causes frequent read and write errors.

Conventionally, as a method to solve the above problem, the air column has a shape in which the width dimension changes in the depth direction of the air column, and the setting position of the tape loop within the column is changed. There is a method of controlling the tape tension to an arbitrary value by changing the column width at the portion where the tape loop contacts the column wall. The above conventional method will be explained below with reference to FIGS. 2 and 3.

In FIG. 2, 1 is a tape that forms a tape loop 10 in the air column 6, and is tensioned by the pressure difference between the atmospheric pressure part 11 and the negative pressure part 12 in the column, and is applied to the take-up reel 5 at a predetermined level. It is wound under a winding tension of . Tape loop 10 in column
The position l is determined by converting the deviation Δl from the set position l _p into a current i by the signal conversion amplification unit 16 and feeding it back to the DC drive motor 14 of the take-up reel 5 _. controlled by. The target value l _p is determined by a preset pattern 15 based on the tape winding diameter d measured on the winding reel 5.
given according to. The air column 6 has a shape in which the width H changes in the depth direction of the column, and the tension generated in the tape changes depending on the position l of the tape loop. That is, as shown in Fig. 3, under atmospheric pressure P _a and negative pressure P _c in the column, tape tension S is given by equation (1), S = 1/2 (P _a - P _c )・B・H ...(1) H: Tape loop is on column wall 17a, 17
Column width of the part in contact with b: B: Tape width This is because it has the property of being proportional to the width H of the column.

However, in the above conventional method, the tape tension is changed by changing the column width at the part where the tape loop contacts the column wall, so it is necessary to obtain a column width change proportional to the desired tape tension change. Therefore, the width of the column had to be changed significantly in the depth direction, which caused the problem that the shape of the air column became complicated.

In view of the above problems, the present invention provides a tape tension control method that can obtain a desired tape tension change without complicating the shape of the air column.

Now, FIG. 4 is an explanatory diagram of an air column in one embodiment of the present invention. As shown in Figure 4,
In one embodiment of the present invention, a column is used in which the dimension of the column in the tape width direction changes in the column depth direction. That is, by changing the gap t formed between the tape edge and the column walls 18a and 18b, the flow rate of air passing through the gap is changed, generally according to the characteristics of the air suction source as shown in FIG. Therefore, the column internal negative pressure P _c is changed, and as it is clear from equation (1), the tape tension S changes as P _c changes.

In addition, if the above-described method of the present invention is used, the column negative pressure P _c changes approximately in proportion to the square of the gap t, as derived from the orifice theory in fluid mechanics. Therefore, compared to the conventional method, which changes the tape tension by changing the column width at the part where the tape loop contacts the column wall, it is possible to obtain the desired tape tension change with a smaller change in the column width. can.

In addition, the change pattern of the tape winding tension can be changed on the take-up reel by, for example, setting the winding tension to decrease as the winding diameter increases, as shown in Figure 6. can prevent the tape from tightening.

In the above embodiment, the tape loop control target position l _p was set by the tape winding diameter detected by the take-up reel, but it may also be set by the tape winding amount, or It is clear that if the time of the tape winding process is fixed, a method of sequentially changing the time depending on the elapsed winding time may be used.

As explained above, according to the present invention, since the inner dimension of the tape in the width direction of the air column changes in the depth direction of the air column, a slight dimensional change in the width direction of the tape of the air column can achieve the desired result. This has the unique effect that the shape of the air column does not become complicated and manufacturing becomes easy.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a tape winding device having an air column, FIG. 2 is a tape tension control device using a conventional method, and FIG. 3 is an explanatory diagram of an air column in which the column width changes in the column depth direction. FIG. 4 is an explanatory diagram of an air column according to an embodiment using the method of the present invention, in which a is a front view and b is a side sectional view. Fifth
The figure shows the characteristics of the air suction source, and FIG. 6 shows the relationship between the tape winding diameter and tape tension. 1...Tape, 6...Air column, 10...
tape loop.

Claims (1)

[Claims] 1 A method for controlling tape tension using an air column, comprising a control system configured to maintain the position of a tape loop in the air column at a predetermined set position, and comprising a control system configured to maintain the position of the tape loop in the air column at a predetermined setting position, and A tape tension control method characterized by having a shape in which the inner dimension changes in the depth direction of the air column, and controlling the tape tension to an arbitrary value by changing the control setting position of the tape loop. .