JP2001110049A - Feed stabilizing method of magnetic tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a feed stabilizing method of magnetic tape which is effective for setting a magnetic tape to be machined at the focal position of a machining laser beam in an extremely accurate way when a laser beam, etc., is incident on the back layer of the magnetic tape to form a recessing part (groove) on the tape back layer. SOLUTION: In this feed stabilizing method which feeds a magnetic tape in its lengthwise direction, a roller feeding means is used. The roller feeding means has the prescribed revolving accuracy (e.g. a <=5% range of laser power attenuation set in a machining state) about a part that requires the vertical position accuracy of the magnetic tape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of magnetic tapes used for recording / reproducing information, and more specifically, slips are generated even when a magnetic tape is transported at a high speed in a magnetic tape manufacturing process or the like. In addition, the present invention relates to a magnetic tape transport stabilizing method capable of preventing the magnetic tape from being damaged or disturbing the winding shape due to the above, and stably transporting the magnetic tape with reduced cupping.

[0002]

2. Description of the Related Art Magnetic tapes used for recording / reproducing information are:
Basically, a base made of a film such as PET (polyethylene terephthalate), a magnetic layer formed on one surface of the base, and a magnetic layer formed on the base for the purpose of improving transport stability and strength. And a back layer formed on the opposite surface.

In the manufacturing process of such a magnetic tape, the magnetic tape (hereinafter, also simply referred to as a tape) is subjected to various processes such as cutting by a slitter and cleaning of a surface by a blade while being conveyed in a longitudinal direction. Then, it is wound up by a hub or the like to be a pancake or a cassette, and sent to the next process or a delivery destination. In recent years, in order to improve productivity, a tape transport speed in various processes (a manufacturing device such as a blade machine or a winder) tends to increase.

[0004] In general, the tape is conveyed by winding the tape around a capstan roller and rotating the capstan roller. However, when the transport speed of the tape is increased, in a manufacturing device such as a blade machine, the tape entrains air, and the tape floats with a capstan roller or the like, which causes the tape to slip, thereby preventing normal transport. In some cases.

As a result, the tape becomes a capstan roller,
The tape collides or improperly contacts the guide roller, blade blade, etc., causing tape damage such as breakage of the tape or tape edge, abrasion or peeling of the magnetic material layer, etc.
It will be inappropriate as a product. A roller for measuring the length of the tape (measurement roller) is attached to the tape manufacturing device as needed. If the tape slips with this measurement roller, an error occurs in the tape length measurement. This causes a problem that production control cannot be performed properly. For this reason, it has been difficult to increase the tape transport speed in tape manufacturing so as to favorably meet the required production efficiency.

As another problem of the magnetic tape, the above-mentioned cupping is known. Cupping is a curl (curvature) in the width direction of a magnetic tape, which is mainly caused by a difference in shrinkage of a binder used between a magnetic layer and a back layer. When cupping occurs, the appearance of the magnetic tape as a product is deteriorated; the contact of the magnetic tape with the recording head and the reading head is deteriorated, which may cause a recording error or a reading error; and the edge of the magnetic tape is easily damaged. The durability is lowered, and various problems occur.

[0007]

Such cupping can be improved by a method such as increasing the thickness of the magnetic layer, reducing the thickness of the back layer, or adjusting the formulation of the magnetic layer or the back layer. There is a limit to improvement due to various problems such as process, formulation, and performance. Specifically, in recent years, the recording density of magnetic tapes has been improving, and in order to achieve this, the thickness of the magnetic layer has been decreasing and the thickness of the backing layer has been reduced. And the problem arises in practical durability. Further, if the prescription of the magnetic layer or the back layer is changed, the characteristics as a magnetic tape fluctuate, and the desired performance may not be obtained. In other words, to reduce the cupping by adjusting the prescription of the magnetic layer and the back layer while preventing the performance from deteriorating is a very time-consuming operation, and it is necessary to reduce the development efficiency and the cost of the magnetic tape. Is disadvantageous.

As another method, it is conceivable to provide a concave portion (groove) in the back layer of the magnetic tape. However, when this method is adopted, a laser beam or the like is applied to the magnetic tape in an actual manufacturing process. In order to maintain processing accuracy when performing processing for forming concave portions (grooves) by making light incident on the back layer, the magnetic tape to be processed must be extremely accurately positioned at the focal position of the processing laser beam. is necessary.

The present invention has been made in view of the above circumstances, and an object thereof is to make a laser beam or the like incident on a back layer of a magnetic tape and to form a recess (groove) in the back layer of the tape. An object of the present invention is to provide a magnetic tape transport stabilization method effective for positioning a magnetic tape to be processed at a focal position of a processing laser beam very accurately, for example, when performing forming processing.

[0010]

In order to achieve the above object, a method for stabilizing the transport of a magnetic tape according to the present invention is characterized in that when the magnetic tape is transported in the longitudinal direction, the positional accuracy of the magnetic tape in the vertical direction is reduced. For the parts requiring the above, a roller conveying means having a predetermined rotation accuracy is used.

Further, the method for stabilizing the transport of a magnetic tape according to the present invention is preferably used as an apparatus in which roller transport means having a predetermined rotational accuracy is provided before and after a portion of the magnetic tape requiring vertical positional accuracy. Can be embodied.

The apparatus for stabilizing the transfer of a magnetic tape embodying the present invention is suitably used for a magnetic tape processing apparatus for laser-processing a magnetic tape. It is preferable that the tape be set so that the attenuation of the power of the laser beam used for the laser processing at the processing position is within 5% of its maximum value. Further, it is preferable that a roller constituting the roller conveying means has a brim slightly smaller than a width of the magnetic tape at both ends thereof.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for stabilizing the transport of a magnetic tape according to the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings. In the embodiments described below, the present invention is applied to a process of forming a concave portion (groove) in a back layer of a magnetic tape by irradiating a laser beam or the like to the back layer of the magnetic tape as described above. For a magnetic tape processing device (hereinafter, also simply referred to as a processing device) for application to a tape transport control unit.

Here, the magnetic tape to which the transport stabilization method according to the present invention can be applied has a magnetic layer on one surface of a base made of PET or aramid resin, and a back layer on the other surface. Alternatively, overcoat layer (protective layer)
A magnetic tape having an ordinary layer configuration, which has a magnetic layer and an undercoat layer, may be used.

FIG. 1 conceptually shows an example of a back layer of a magnetic tape processed by a tape processing device in a magnetic tape handling device according to this embodiment. In the example shown in FIG. 1A, a plurality of processing lines a extending in the longitudinal direction of the tape are formed on the back layer of the tape.
The example shown in FIG. 1B is an example in which the processing of the back layer is intermittent and the processing line is divided (shown by b) in the example shown in FIG. 1A. Here, the length of the processing line segment b is not particularly limited. Further, the lengths of the processing line segments b may be the same, or line segments having different lengths may be mixed.

A tape having a concave portion (processed line, processed line segment) in the back layer as shown in FIG. 1 also has less cupping, which is curl in the width direction of the tape, than the conventional tape. As a result, deterioration in appearance, deterioration of head contact, damage to the tape edge, and the like due to the above-mentioned problems are greatly reduced as compared with the conventional tape. Furthermore, even when the tape is conveyed at a high speed in a tape manufacturing apparatus such as a blade machine or a winder, the entrainment of air by the tape is reduced, and even when air is entrained, the air is suitably removed from the processing line. be able to.

Further, even when the tape is transported at high speed, the tape does not rise and slip due to the capstan roller or the like of the manufacturing apparatus, so that there is no damage to the tape or an error in the transport length. By performing appropriate tape conveyance, magnetic tapes of appropriate quality can be stably and efficiently manufactured under appropriate production management. Also, when rewinding,
Since the air between the tapes can be suitably removed, the appearance of the roll when wound on a cartridge or pancake is also beautiful.

There is no particular limitation on the shape (cross-sectional shape) of the above-mentioned concave portion. For example, a rectangular shape as shown in FIG. 2A, a triangular shape as shown in FIG. C)
And a semicircle (bow) as shown in FIG. These shapes can be realized by adjusting the intensity distribution (profile) of the beam spot of the laser beam used when processing the back layer.

There is also no particular limitation on the depth of the concave portion. In general, the tape width, the material and thickness of the back layer, the material and thickness of the base, the process after the concave portion formation and the user's point of view. In consideration of the load (transport speed, tension, etc.) on the tape such as the processing of
It may be determined appropriately. As an example, the depth of the recess is
0.1 μm or more, particularly preferably 0.2 μm
It is more preferable to make the above.

Further, the size (line width) and formation density of the concave portion are not particularly limited, and may be appropriately determined according to the strength and width (size) of the tape. When forming a processing line or the like extending in the longitudinal direction as shown in FIGS.
It is preferable to form several to about 100 processing lines in the width direction with a width of about 3 μm to 10 μm.

FIG. 3 shows a conceptual diagram of a tape processing apparatus used for producing the above-described magnetic tape. The processing apparatus 10 in the illustrated example is similar to the processing apparatus 10 shown in FIGS.
A light source 12 for forming a processing line extending in the longitudinal direction of the tape as shown in FIG.
And an optical system including a pulse modulator 14, a mirror 16, a beam expander 18, a beam profile shaper 20, and a multi-lens lens 22, and a tape transport unit 24.

In such a processing apparatus 10, the (magnetic) tape T is emitted from the light source 12 while being transported in the longitudinal direction (the direction of the arrow x in the figure) while the (magnetic) tape T is positioned at a predetermined processing position by the tape transport means 24. A processing line is formed on the tape by irradiating the laser beam to the processing position by an optical system. Here, the tape T is transported with its back layer facing upward (toward the laser beam incidence side), and accordingly, the back layer of the tape T is processed by the laser beam.

As the light source 12, any light source (laser oscillator) can be used as long as it has an output capable of processing the back layer of the tape T. Preferably, a laser beam in the ultraviolet or visible region is used. One that can emit at least one is used. From the viewpoint of workability, a laser beam having a short wavelength is preferable, and a laser beam in the ultraviolet region is most preferable. However, a laser beam in the visible region is preferable in terms of cost, safety, workability, and the like. In particular,
A light source that emits a 532 nm laser beam obtained by wavelength-converting an 488 nm or 515 nm argon (ion) laser or a YAG laser with an SHG (second harmonic generation) element is exemplified.

The pulse modulator 14 modulates the pulse of the laser beam in order to form a processing line segment as shown in FIG. Therefore, when the light source 12 can directly perform pulse modulation or when only the processing line as shown in FIG. 1A is formed, the pulse modulator 14 is unnecessary. As the pulse modulator 14, known modulation means such as an AOM (acoustic optical modulator) can be used. Further, by adjusting the modulation period, the length of the processing line segment can be adjusted.

The laser beam is reflected by the mirror 16 in a predetermined direction, and then enters the beam expander 18. The processing apparatus 10 according to the present embodiment divides one laser beam to form a processing line on the tape T, but applies the processing line to the entire surface in the width direction corresponding to the tape T having various widths. Preferably it is formable. However, in general, the diameter of the laser beam emitted from the light source is about 1 mm, and the width of the tape T is wider than that, so that the entire surface of the tape T in the width direction cannot be processed as it is.

For this reason, in the processing apparatus 10, the beam expander 18 is arranged to expand the diameter of the laser beam emitted from the light source 12. For example, when the diameter of the laser beam emitted from the light source 12 is 1 mm and the width of the tape T is 0.5 inch, the diameter of the laser beam may be increased about 15 to 20 times. Further, it is preferable that the diameter expansion rate of the laser beam in the beam expander 18 is adjustable.

The laser beam expanded in diameter by the beam expander 18 is then transmitted to a beam profiler 20.
(Hereinafter, simply referred to as a molding device 20). Molding machine 2
0 makes the intensity of the laser beam substantially uniform over the entire beam spot, that is, makes the intensity distribution of the laser beam substantially uniform.

Normally, since the laser beam emitted from the light source 12 has an intensity distribution such as a Gaussian distribution,
When the tape T is processed by this laser beam, the depth of the processing line varies depending on the intensity distribution. Therefore, by disposing the molding device 20, the intensity distribution of the laser beam can be made uniform, and the depth of the processing line to be formed can be made uniform. As the forming device 20, various optical filters, an aperture having the same diameter as a laser beam for forming a beam profile using Fresnel diffraction, a multi-lens lens, and the like can be used.

The laser beam is then applied to the multi-lens 22
Incident on. The multi-lens lens 22 is formed by arranging a large number of microball lenses and selfoc lenses in a direction perpendicular to the optical axis with its optical axis parallel to the laser beam. The laser beam is divided, incident on a predetermined processing position, and imaged. Thus, the back layer of the tape T is processed by the laser beam to form a processing line or the like (recess).

FIG. 4 is a schematic diagram showing one example of the structure viewed from the optical axis direction. The multi-lens lens 22 in the illustrated example is, for example, a microball lens or a selfoc lens (hereinafter, both are collectively referred to as a lens) in which 5 × 5 lenses are arranged in a close-packed state, as shown in FIG. As described above, the lens arrangement line indicated by the alternate long and short dash line is arranged with a slight inclination with respect to the transport direction x and the width direction of the tape T.
Thereby, the tape T is transported once in the longitudinal direction (one pass).
By simply doing so, a total of 25 (rows) processing lines a extending in the longitudinal direction can be formed.

Here, the distance between the processing lines a can be adjusted by adjusting the angle between the transport direction x and the lens arrangement line, but in order to form the processing lines efficiently,
This angle is the optical axis of each lens (the center of the beam waist)
Must be set so as not to overlap in the transport direction x.
For example, when paying attention to the lens arrangement line in the width direction of the tape T, if the number of multi-lens lenses in one row is N; and the angle between the transport direction x and the arrangement line is θ; Means that the optical axes of the lenses do not overlap in the transport direction x. sin [(2π / 3) + θ] ≧ N · sin θ Note that the lens arrangement of the multi-lens is not limited to the close-packed state shown in FIG. 4, and various types can be used.

In the processing apparatus 10 shown in FIG. 3, the tape T is moved to a predetermined processing position by the tape transport means 24 so that the back layer side (back side) faces upstream (laser beam incident side) of the laser beam optical path. (That is, the transport direction x and the longitudinal direction are matched) while being transported in the longitudinal direction. The tape transport means 24 includes transport drive means (not shown) such as a capstan roller, a rewinder, and a winder; guide rollers 26 and 28;
And a tape flattener 30.

The tape flattener 30 is made up of high-precision flanged rollers 30a and 30b, as described later, and comes into contact with the surface (magnetic layer side) of the tape T to be conveyed, and It is positioned (held) at a predetermined processing position. In the transport direction x, the tape T forms a transport path that passes below the tape flattener 30 by the guide rollers 26 and 28 that are disposed with the brim rollers 30a and 30b interposed therebetween. As a result, the tape T is pressed and supported by the tape flattener 30, and is positioned at the processing position.

In the tape processing apparatus 10 according to the present embodiment, the processing by the laser beam is performed with a width of 3 μm to 10 μm as described in the above-mentioned example of the tape T having a width of 0.5 inch.
Since the processing is fine processing such as μm, the beam spot diameter incident on the processing position is small, that is, the allowable range of the beam waist is very narrow. Therefore, as described above, the flanged rollers 30a and 30b constituting the tape flattener 30 are required to position the tape T with high precision in the depth of focus direction of the multi-lens 22.

As described above, the light is emitted from the light source 12 at the processing position, modulated by the pulse modulator 14 as necessary, reflected by the mirror 16, expanded by the beam expander 18, and expanded by the forming device 20. The intensity distribution is made uniform, and a laser beam divided and modulated by the multi-lens lens 22 enters and forms an image.

Therefore, with the tape conveying means 24, the flanged rollers 30a, 30a constituting the tape flattener 30 with the back side facing upstream of the laser beam optical path.
The tape T is transported in the longitudinal direction while being positioned at the processing position by b, so that the back layer of the tape T
A processing line (recess) extending in the longitudinal direction is formed. In the above-described example, 25 processing lines are formed by one transfer.

In the tape processing apparatus 10, the tape T
In many cases, the processing of the back layer generates processing dust and gas such as dust. Therefore, in the vicinity of the processing position, a removing unit for removing the above-described processing waste and gas,
For example, it is desirable to provide a dust removing unit including an ion wind blowing unit and a suction unit for inhaling dust and the like that have been separated and floated by the ion wind.

As described above, when the laser beam is made incident on the back layer of the tape T to form a concave portion (a groove, a processing line or a processing line segment), the processing accuracy is maintained. In addition, it is necessary to extremely accurately position the tape T to be processed at the focal position of the laser beam. FIG. 5 shows details of the tape transport control unit in the processing apparatus for this purpose.

In FIG. 5, reference numeral 102 denotes an optical head of the laser displacement meter, which includes a light projecting unit and a light receiving unit. The optical head is adjusted so that the laser beam emitted from the light projecting unit and reflected by the object (tape T) is received by the light receiving unit. Reference numeral 104 denotes a control unit that performs measurement control of the optical head 102 and outputs a position measurement result of the tape T to display means (not shown).

As shown in FIG. 6, the flanged rollers 30a and 30b constituting the tape flattener 30 have flanges 3a having a height of about 1 mm to 3 mm at both ends thereof.
1 and 31 are special rollers having a width (surface length) slightly smaller than the width of the tape T and having curved end portions 32 at both ends. The rotation accuracy (axis runout)
Has the precision as described below.

First, the surface lengths of the flanged rollers 30a and 30b are made slightly smaller (specifically, for example, about 1%) than the tape width. When the surface lengths of the rollers 30a and 30b are the same as the tape width, as shown in FIGS. 7A and 7B, the initially flat roller surface (FIG. 7A)
(See FIG. 7B) to prevent the tape T from being damaged due to the formation of dents 33 at both ends due to wear (see FIG. 7B).

The surface shape of both ends of the brim rollers 30a, 30b is formed into a curved surface as shown in FIG. 6 so that the both ends of the brim rollers 30a, 30b are narrower than the width of the tape T. There is an effect that the familiarity of the tape T between the brims of the part can be improved.

On the other hand, in the laser processing of the tape T as described above, the focal position of the laser beam is, in practice, centered on the position where the laser power is at its maximum value, and before and after that position. The range including 95% or more of the value may be considered. The depth of the focus position of the practical laser beam varies depending on the spot diameter of the laser beam. For example, when the spot diameter of the laser beam is 10 μm, the depth of the focus position is about 3 μm.
0 μm.

Therefore, the ribbed rollers 30a and 30b constituting the tape flattener 30 need to be formed so as to clear this accuracy. More specifically, the shaft runout of the flanged rollers 30a and 30b is set to a dimension corresponding to, for example, a range in which the attenuation of the power of the processing laser light (laser beam) is within 5% of its maximum value. Anything should do.

The tape transport control unit of the present embodiment configured as described above regulates the position in the width direction by the flanged roller and also regulates the position in the height direction by the rotational accuracy of the flanged roller itself. In addition, when the present invention is applied to an apparatus that performs laser processing of the tape T, the tape T can be transported extremely stably.

In the tape transport control section of this embodiment, the laser beam emitted from the light projecting section of the optical head 102 of the laser displacement meter and reflected by the tape T is received by the light receiving section. For example, by outputting position information of the laser beam on the light receiving surface to a display device or the like, it is possible to monitor a change in the state of the shaft runout of the flanged rollers 30a and 30b, and based on the result, replace the laser light appropriately. Can be taken.

That is, when the tape T is at the above-mentioned processing position, no special treatment is required. However, when the position of the tape T is out of the above-mentioned processing position, the flanged rollers 30a and 30b are replaced with new ones. It is possible to take measures such as exchanging things. At this time, it is also possible to notify the operator of the situation that the replacement is required, by voice, turning on a warning lamp, or the like.

According to the above embodiment, when the tape T is processed while being conveyed in the longitudinal direction, the tape position can be maintained at a predetermined position by the flanged rollers 30a and 30b of the tape conveyance control unit. In addition, when performing processing such as laser processing, there is an effect that position accuracy can be accurately obtained.

The above embodiments are merely examples of the present invention, and the present invention is not limited to these embodiments. For example, in the above-described embodiment, an example in which the present invention is applied to a tape processing apparatus by laser processing has been described. However, the present invention can be widely applied to other apparatuses involving tape transport.

Further, for example, the flanged rollers 30a, 30
The height and thickness of the brim of 0b, the curvature of the curved portion at both ends, and the like may be appropriately determined depending on the type and thickness of the tape T. Further, as for the method of checking the shaft runout state of the flanged rollers 30a and 30b by monitoring the position of the tape T, it goes without saying that other position monitoring methods other than the means shown in the embodiment may be used. Absent.

[0051]

As described above in detail, according to the tape transport stabilizing method according to the present invention, a laser beam or the like is incident on the back layer of the magnetic tape, and the concave portion ( When processing to form grooves)
The effect is obtained that the magnetic tape to be processed can be positioned very accurately at the focal position of the processing laser beam.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams illustrating examples of processing lines (recesses) formed on a back layer of a tape by a tape processing method.

FIGS. 2A, 2B, and 2C are diagrams showing cross-sectional shapes of processing lines (recesses) formed on a back layer of the tape by a tape processing method.

FIG. 3 is a conceptual diagram showing a main part of a tape processing device to which the present invention is applied.

4 is a conceptual diagram for explaining a multi-lens used in the magnetic tape processing device shown in FIG.

FIG. 5 is a diagram illustrating a configuration of a magnetic tape transport control unit according to the embodiment.

6 is a roller 30a, 30b with a brim shown in FIG.
FIG.

FIG. 7A is a diagram showing an initial state of a flanged roller, and FIG. 7B is a diagram showing a worn state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 (Tape) processing apparatus 12 Light source 14 Pulse modulator 16 Mirror 18 Beam expander 20 (Beam profile) shaper 22 Multi-lens lens 24 Tape transport means 26, 28 Guide roller 30 Tape flatner 30a, 30b Flanged roller 31 Flange 32 Curved surface processing section 102 Optical head of laser displacement meter 104 Same as above, control unit

Claims (1)

[Claims] 1. A method for stabilizing the conveyance of a magnetic tape in a longitudinal direction, wherein a roller conveying means having a predetermined rotation accuracy is used for a portion of the magnetic tape which requires a vertical position accuracy. Characteristic method of stabilizing the transport of magnetic tape.