JP2003228822A - Method for manufacturing magnetic tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a magnetic tape wherein no writing errors occur when a servo signal is written in the width direction end of the magnetic tape. <P>SOLUTION: When a narrow magnetic tape 26 is manufactured by transporting a wide belt-like magnetic tape roll 20 and cutting it with a slitter 14 constituted of a rotary upper knife 32 and a rotary lower knife 30, the cutting is carried out by setting the peripheral speed of the rotary lower knife 30 slower than the transport speed of the magnetic tape roll 20. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a magnetic tape, and more particularly to a method for manufacturing a magnetic tape for computer data backup. 2. Description of the Related Art In the production of various magnetic tapes, such as cassette tapes and video tapes, which are also used for computer data backup, they are wide and wound in a roll on a rewinding reel. A strip of magnetic tape is continuously pulled out via a plurality of guide rollers, conveyed to a slitter, and cut with the slitting upper and lower blades to produce multiple narrow magnetic tapes. A cutting process is performed. As shown in Japanese Patent Laid-Open No. 3-12822, the relationship between the rotary blade and the conveyance speed of the magnetic tape original in this cutting process is the same as the traveling speed of the magnetic tape original. , It is cut at a faster speed than that. JP-A-3-29
In Japanese Patent No. 2624, cutting is performed such that the peripheral speed of the rotary blade is 1 to 1.5 times the conveying speed of the original magnetic tape. By the way, the magnetic tape also has a high track density in accordance with the recent demand for high density recording and high capacity. In order to accurately track the recording track and read it with the magnetic head, the width variation of the magnetic tape is required. Need to be small. For this reason, in the case of cassette tapes, video tapes, etc., the width variation of the magnetic tape is 10 μm.
It is required to cut to fit within. On the other hand, in the field of computer data backup magnetic tape, a system for tracing with a servo signal written in advance at least at one end in the width direction of the magnetic tape is becoming mainstream, and therefore, a higher accuracy in width dimension is required. Therefore, it is required to cut the width dimension variation so as to be within 5 μm. In order to satisfy such a requirement for a high-precision width dimension, a slitter having a high-precision cutting precision capable of suppressing the width dimension fluctuation amount to within 1 μm is used regardless of the width dimension of the magnetic tape to be cut. doing. However, even though a slitter having a high cutting accuracy is used, a writing error may occur in the process of writing a servo signal on the magnetic tape. There's a problem. The present invention has been made in view of such circumstances, and a magnetic tape capable of producing a magnetic tape that does not cause a write error when a servo signal is written to an end portion in the width direction of the magnetic tape. It aims at providing the manufacturing method of a tape. In order to achieve the above-mentioned object, the present invention cuts with a slitter composed of a rotating upper blade and a rotating lower blade while conveying a wide strip of magnetic tape. Thus, in the magnetic tape manufacturing method for manufacturing a plurality of narrow magnetic tapes, the peripheral speed of at least the rotating lower blade of the rotating upper blade and the rotating lower blade is slower than the conveying speed of the original magnetic tape. And cutting. Since the servo signal is written along the shape of the edge in the width direction of the magnetic tape even if the width variation of the cut magnetic tape is within the above-mentioned requirement, the inventor If the period of the wave shape of the edge of the magnetic tape due to the fluctuation, that is, the interval between the crest and crest or the valley and trough of the wave is short, the servo signal write head cannot follow the short period wave shape and write error occurs. The knowledge that it becomes easy to generate is obtained. In addition, the change in the cycle of the width dimension fluctuation always involves the change in the surface runout period of the rotating lower blade that is the receiving blade side at the time of cutting. The knowledge that it can be prolonged was acquired. Based on such knowledge, in the present invention, when cutting a narrow magnetic tape with a slitter composed of a rotating upper blade and a rotating lower blade while conveying a wide belt-shaped magnetic tape original, Since the peripheral speed of at least the rotating lower blade of the blade and the rotating lower blade is made slower than the conveying speed of the magnetic tape original fabric, the cycle of fluctuation in the width dimension can be lengthened. This makes it easy for the write head to follow the waveform of the edge of the magnetic tape, so that no write error can occur when writing a servo signal on the magnetic tape.
In this case, even if the peripheral speed of the rotating upper blade is made slower than the conveying speed of the magnetic tape original together with the rotating lower blade, the width variation cycle can be lengthened. Therefore, it is preferable that the peripheral speed of only the rotating lower blade is made slower than the conveying speed of the original magnetic tape. In addition, by slowing down the rotation speed of the rotating lower blade, the original magnetic tape is less affected by the rotation of the rotating lower blade, so that the straightness in conveying the original magnetic tape is improved. In a preferred embodiment of the present invention, when the conveying speed of the magnetic tape original is 100%, the peripheral speed of at least the rotating lower blade of the rotating upper blade and the rotating lower blade is 10-9.
It is preferable to be 5%, and more preferably 10 to 50%. As a preferred embodiment of the present invention, it is preferable to make the wrap angle of the original magnetic tape wrapped on the rotating lower blade on the receiving blade side shallower to 40 ° or less, preferably 20 ° or less. Furthermore, it is preferable that the tension in the conveying direction of the magnetic tape original at the time of cutting is 50 to 200 g per 1/2 inch of the magnetic tape original. Thereby, even when the peripheral speed of the rotating upper blade and the rotating lower blade is made slower than the conveying speed of the magnetic tape original fabric, the sharpness and cutting stability at the time of cutting can be maintained well. In a preferred embodiment of the present invention, the peripheral speed of the rotating upper blade and the rotating lower blade is controlled to convey the magnetic tape original in the speed increasing range in which the conveying speed of the original magnetic tape at the start of cutting is increased. At the same speed as the speed, when the transport speed is in the high-speed transport constant speed range set for cutting, the peripheral speed of at least the rotating lower blade of the rotating upper blade and the rotating lower blade is set to the magnetic tape original. Make it slower than the opposite conveyance speed. In this way, after the conveying speed of the original magnetic tape becomes sufficiently high, the peripheral speed of at least the rotating lower blade of the rotating upper blade and the rotating lower blade is lowered, so that the sharpness and cutting stability at the time of cutting are reduced. Can be maintained well. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of a magnetic tape manufacturing method according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a block diagram showing an example of a cutting apparatus to which the magnetic tape manufacturing method of the present invention is applied, and FIG. 2 is a side view of a slitter. As shown in FIG. 1, the cutting device 10 mainly comprises a rewind reel 11, a slitter 14, and a plurality of take-up reels 17. On the hub 12 of the rewind reel 11, a bulk of the magnetic tape 20 wound in a roll shape is mounted. The magnetic tape 20 is usually formed by forming a magnetic layer containing ferromagnetic fine particles on a nonmagnetic support by a coating method, a vacuum deposition method, or the like, and subjecting the magnetic layer to orientation treatment, drying treatment, surface treatment, and the like. Manufactured by. The slitter 14 is a device for cutting a wide and strip-shaped magnetic tape 20 into a plurality of magnetic tapes 26, 26,... By a pair of upper and lower rotary blades 30, 32. FIG.
As shown in FIG. 4, a thin disk-shaped plurality of blades that are formed as a receiving blade in a roller shape and cut by applying a shearing force to the magnetic tape 20 between the rotating lower blade 30 and the rotating lower blade 30. The rotating upper blades 32, 32. Rotating lower blade 30
Is fitted and fixed to the lower shaft 34 via a spacer 36, and the rotary upper blade 32 is fitted and fixed to an upper shaft 38 parallel to the lower shaft 34 via a spacer 40 to rotate with the rotary upper blade 32. The blade tip portions with the lower blade 30 are arranged so as to overlap each other. The rotating upper blade 32 is urged to the right in the axial direction of FIG. 2 by a spring (not shown), and is positioned in a state in which the cutting edge portion of the rotating upper blade 32 is in contact with the cutting edge portion of the rotating lower blade 30. The upper shaft 38 and the lower shaft 34 are respectively connected to motors 41 and 43 whose rotation speeds can be freely changed, and the peripheral speeds of the rotary upper blade 32 and the rotary lower blade 30 can be individually changed. As shown in FIG. 1, between the rewind reel 11 and the slitter 14, a plurality of guide rollers 22, 22,... A ground suction drum 24 that regulates the transport speed is provided. The ground suction drum 24 is connected to a motor (not shown) whose rotational speed can be freely changed. By rotating the magnetic tape original 20 on the peripheral surface of the ground suction drum 24, the ground suction drum 24 is rotated.
The conveyance speed of the magnetic tape original 20 is arbitrarily changed. The rotational speed of the hub 18 of the take-up reel 17 is controlled based on the peripheral speed of the ground suction drum 24. The means for restricting the conveying speed of the magnetic tape original 20 is not limited to the ground suction drum 24, and a pinch roller that sandwiches and conveys the magnetic tape 20 can also be used. Also, a plurality of guide rollers 22, 2
Of the two,..., The guide roller 22 positioned immediately upstream of the slitter 14 and the guide roller 2 positioned closest to the downstream side.
2 is provided with a moving means 23, respectively.
3, the wrap angle for wrapping the magnetic tape original fabric 20 on the rotating lower blade 30 is arbitrarily adjusted by moving the guide roller in the AB direction. Here, the wrap angle is, as shown in FIG. 3, when a horizontal line 29 is drawn on the rotating lower blade 30 so as to pass through the center O of the contact surface where the original magnetic tape 20 and the rotating lower blade 30 are in contact. The angle θ ₁ formed by the horizontal line 29 and the original magnetic tape 20 before contacting the rotating lower blade 30, and the formed magnetic tape 20 after contacting the horizontal line 29 and the rotating lower blade 30. Expressed as the sum of the angle θ ₂ . Moreover, the moving means 23 is a magnetic tape original fabric 2
In addition to adjusting the wrap angle for wrapping 0 to the rotating lower blade 30, the tension in the transport direction of the magnetic tape original 20 is adjusted. Next, the cutting apparatus 10 constructed as described above.
A cutting method for cutting the wide magnetic tape 20 into a plurality of narrow magnetic tapes 26 will be described. When the operation of the cutting apparatus 10 is started, the magnetic tape original 20 is continuously drawn from the rewind reel 11 by the rotation of the ground suction drum 24,
It is conveyed to the slitter 14. Then, it is cut into a plurality of magnetic tapes 26 by the slitter 14 and taken up by the hub 18 of the take-up reel 17. Thereby, for example, the magnetic tape original fabric 20 is cut into 100 to 500 pieces, and specified width dimensions (for example, 12.65 mm, 25.4 mm, 3.81 mm).
Etc.) is produced. Magnetic tape 2 in such a cutting apparatus 10
In the cutting speed of 0, the peripheral speed of the rotating upper blade 32 and the rotating lower blade 30 is the same as the conveying speed of the magnetic tape original 20 in the speed increasing range in which the conveying speed of the original magnetic tape 20 is increased at the start of cutting. When the speed reaches the constant speed range where the constant speed conveyance is performed at a high speed of 400 to 500 m / min, the rotational speed of the motor 41 for rotating the rotating lower blade 30 is decreased to change the peripheral speed of the rotating lower blade 30 to the magnetic tape. It is slower than the conveying speed of the original fabric 20. In this case, if the peripheral speed of the rotary lower blade 30 is lowered in the speed increasing region where the conveying speed of the magnetic tape original fabric 20 is increasing, excess stress is applied to the magnetic tape original fabric 20 such as cracks in the magnetic layer. This is not preferable because it tends to cause failure. Further, even when the peripheral speed of the rotating lower blade 30 is lowered in a constant speed region, if the peripheral speed is suddenly lowered, sudden stress is applied to the magnetic tape 20, so the peripheral speed of the rotating lower blade 30 is gradually decreased. It is preferable to go. The relationship between the conveying speed of the original magnetic tape 20 in the constant speed region and the peripheral speed of the rotating lower blade 30 is as follows.
It is preferable that the peripheral speed of the rotary lower blade 30 be in the range of 10 to 95%, more preferably 10 to 50% when the conveyance speed of 0 is set to 100%. In order to clearly change the width fluctuation period of the cut magnetic tape 26, the peripheral speed of the rotating lower blade 30 may be reduced to about 95% with respect to the transport speed of the original magnetic tape 20. This is because if the peripheral speed of the rotating lower blade 30 is less than 10%, the slitter 14 has a problem in terms of sharpness. Further, in order to maintain the sharpness and cutting stability in the slitter 14 well, together with the control to make the peripheral speed of the rotating lower blade 30 slower than the conveying speed of the magnetic tape original 20 in a constant speed region. It is preferable that the wrap angle of the original magnetic tape 20 wrapped by the rotating lower blade 30 is shallowed to 40 ° or less, preferably 20 ° or less. In this case, the wrap angle wrapped by the rotary lower blade 30 is kept deep in a state where the peripheral speed of the rotary lower blade 30 is low with respect to the conveyance speed of the original magnetic tape 20 (normally, the wrap angle is 50 to 60 °). Since the contact area between the rotating lower blade 30 and the magnetic tape original fabric 20 is large, the slip resistance of the magnetic tape original fabric 20 on the circumferential surface of the rotating lower blade 30 is increased. As a result, the original magnetic tape 20 on the upstream side of the slitter 14 is easily loosened. Therefore, it is preferable to make the wrap angle shallower as the peripheral speed of the rotating lower blade 30 is made slower than the conveying speed of the magnetic tape original fabric 20. Thereby, while preventing slack of the magnetic tape original fabric 20, the rotation upper blade 32 is made by making a wrap angle shallow.
Since the action of tearing the magnetic tape original fabric 20 is added by the rotating lower blade 30, the sharpness can be maintained. Further, the tension in the conveying direction of the magnetic tape original 20 during cutting is 50 to 200 g per 1/2 inch of the magnetic tape original.
It is preferable that Also in this case, it is preferable to increase the tension of the magnetic tape original as the peripheral speed of the rotating lower blade 30 is made slower than the conveying speed of the magnetic tape original 20, that is, as the wrap angle becomes shallower. This makes it possible to lengthen the fluctuation cycle of the width dimension D of the magnetic tape 26 cut as shown in FIG. 4 without adversely affecting the sharpness and cutting stability. For example, the period of width variation when the peripheral speed of the rotating lower blade 30 and the transport speed of the raw magnetic tape 20 is the same speed, i.e. the wave shape of the period of the magnetic tape 26 edge When L _1, rotating lower blade corrugated period of the magnetic tape 26 edge when the slow circumferential velocity of 30 to 50% of the conveying speed of the raw magnetic tape 20 becomes L _2, the period is doubled. Therefore, when writing a servo signal to the end of the magnetic tape 26 in the width direction,
Since the write head (not shown) can easily follow the waveform of the edge of the magnetic tape 26, it is possible to prevent a write error from occurring. As described above, according to the magnetic tape manufacturing method of the present invention, a magnetic tape that does not cause a write error when a servo signal is written to the end portion in the width direction of the magnetic tape. Can be manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a cutting apparatus to which a magnetic tape manufacturing method of the present invention is applied. FIG. 2 is a side view of a slitter. FIG. 4 is an explanatory view for explaining the operation of the present invention. FIG. 4 is an explanatory view for explaining the operation of the present invention. Description of reference numerals 10... Cutting device, 11.
14 ... slitter, 17 ... take-up reel, 18 ... hub, 20
... Magnetic tape raw material, 22 ... Guide roller, 23 ... Moving means, 24 ... Ground suction drum, 26 ... Magnetic tape, 30 ... Rotary lower blade, 32 ... Rotary upper blade, 34 ... Lower shaft, 36 ... Spacer, 38 ... Upper shaft, 40 ... Spacer, 41 ... Motor, 43 ... Motor

Claims (1)

[Claims] [Claim 1] A plurality of narrow magnetic tapes are manufactured by cutting with a slitter composed of a rotating upper blade and a rotating lower blade while conveying a wide strip of magnetic tape. In the method of manufacturing a magnetic tape, the cutting of the magnetic tape, wherein the peripheral speed of at least the rotating lower blade of the rotating upper blade and the rotating lower blade is made slower than the conveying speed of the magnetic tape raw material is cut. Production method.