JPH10269560A - Magnetic recording tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce damage in the vicinity of a tape end surface to increase durability by forming a projecting part in the slit end surface of a tape cross direction while setting a full thickness to a specified value or lower. SOLUTION: A magnetic layer 7 and a protective layer 8 are sequentially stacked in the upper surface of a high polymer film, a back coat 9 is formed in its lower surface, and a projecting part 11 is formed so as to be extended to overlap and be spaced from both slit end surfaces 10 of the high polymer film 6 of a tape cross direction. The full width of a magnetic recording tape composed of the high polymer film 6, the protective layer 7 and the back coat 9 is set equal to or lower than 8 μm. By the spring effect of the projecting part formed in the slit end surface, the upper and lower direction regulating force of a magnetic recording tape traveling system applied to the slit end surface is reduced and thus, the occurrence of one-side extension of a tape end surface as the slit end surface is prevented without any damage to the magnetic layer in the vicinity of the slit end surface or fracturing of the magnetic layer into powders to cause the increase of dropout.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording tape used for information equipment, video equipment and the like.

[0002]

2. Description of the Related Art In the field of magnetic recording, high performance such as digitization, resource saving, miniaturization, and long time has been advanced. Along with that, the demand for magnetic recording tapes has also increased,
In order to increase the density, a thin-film deposited magnetic recording tape in which a ferromagnetic material is directly deposited on a film from a conventional coated magnetic recording tape by a vacuum apparatus is becoming mainstream. In addition, the film thickness is becoming thinner in order to cope with longer time and smaller size.

As the tape magnetic layer thickness and the film thickness decrease, the stiffness of the magnetic recording tape decreases in proportion to the cube of the thickness of the magnetic recording tape. When the stiffness of the magnetic recording tape decreases, the running durability of the magnetic recording tape generally deteriorates.

A conventional magnetic recording tape will be described below. Generally, a disk-rotating slitter used for cutting a magnetic recording tape has a rotating shaft 1 as shown in the configuration diagram of FIG.
The magnetic recording tape 5 is cut in the longitudinal direction at a predetermined width between the rotary thin blade 2 rotating around the rotary blade 3 and the rotary thick blade 4 rotating around the rotary shaft 3. The shape of the slit end face of the magnetic recording tape cut in the longitudinal direction is such that a magnetic layer 7 and a protective layer 8 are sequentially laminated on an upper surface of a polymer film 6 and a lower surface as shown in a sectional configuration view of the slit end face in FIG. Has a back coat 9 laminated thereon. In addition,
Reference numeral 10 denotes a slit end face of the magnetic recording tape.

Conventionally, the slit end face 10 obtained by cutting the above magnetic recording tape has a magnetic layer 7 near the slit end face 10, a surface of the polymer film 6, and a back coat 9 formed by running on a magnetic recording tape running system such as a VTR. Surface is cut off, causing dropout. In order to prevent this, the cutting conditions at the time of cutting have been optimized so that the cut slit end faces 10 are uniform. Further, burnishing or the like is performed on the slit end face 10 to make the slit end face 10 uniform.

[0006]

However, in the above-described conventional configuration of the slit end face, even if the slit end face is made uniform by cutting conditions or burnishing at the time of cutting, if the total thickness of the magnetic recording tape becomes 8 μm or less. The stiffness in the tape width direction decreases in proportion to the cube of the total thickness of the magnetic recording tape.
The magnetic layer in the vicinity of the slit end face of the magnetic recording tape is damaged by the upper and lower restricting forces of the magnetic recording tape traveling system, etc., the magnetic layer is scraped and powdered to increase the dropout, and the tape end face which is the slit end face One-sided elongation occurred.

An object of the present invention is to solve the above-mentioned conventional problems, and it is an object of the present invention to reduce the damage near the end face of a magnetic recording tape and increase the durability.

[0008]

In order to achieve this object, the present invention provides a magnetic recording tape having a total thickness of 8 μm or less and a projection formed on a slit end face in a tape width direction, or a total thickness of 8 μm or less. A magnetic recording tape in which cracks are formed in the magnetic layer surface in the tape longitudinal direction within 0.5 mm from the end surface in the tape width direction. With such a configuration, damage near the tape end surface during tape running can be reduced. It is possible to reduce the durability and increase the durability.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is a magnetic recording tape having a total thickness of 8 μm or less and a convex portion formed on a slit end surface in a tape width direction. Due to the spring effect, the vertical restraining force of the magnetic recording tape running system applied to the slit end face is weakened, the magnetic layer near the slit end face is damaged, the magnetic layer is scraped and powdered, dropout increases, and the slit end face is increased. The occurrence of one-sided stretching of the tape end face is eliminated.

According to a second aspect of the present invention, the total thickness is 8 μm or less, and the thickness is 0.1 mm from the slit end face of the magnetic recording tape.
A magnetic recording tape in which cracks are formed in the longitudinal direction of the magnetic recording tape on the surface of the magnetic layer within 5 mm. The magnetic layer near the slit end face is damaged,
The magnetic layer is scraped and powdered, thereby increasing dropouts and preventing the tape end face, which is the slit end face, from being stretched.

According to a third aspect of the present invention, there is provided a magnetic recording tape having a total thickness of 8 μm or less and having a combination of the projections of the first aspect and the cracks of the second aspect. The spring effect and the cushion effect of the crack absorb the vertical restraining force of the magnetic recording tape running system applied to the slit end face, and the one-sided stretching of the magnetic recording tape is eliminated.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 is a sectional configuration view of a slit end surface of a magnetic recording tape according to Embodiment 1 of the present invention.
The same components as those in FIG. 3 showing the cross-sectional configuration of the slit end surface of the conventional magnetic recording tape are denoted by the same reference numerals and described.
A magnetic layer 7 and a protective layer 8 are sequentially laminated on the upper surface of the polymer film 6, and a back coat 9 is laminated on the lower surface, and both slit end faces 1 of the polymer film 6 in the tape width direction are provided.
A convex portion 11 is formed so as to extend so as to overlap with a gap at zero.

Incidentally, the projections 11 of the slit end face 10 described above.
Is a convex portion formed by controlling the plastic flow due to the compressive stress at the time of cutting of the magnetic recording tape by cutting conditions when cutting with the general disk-rotating slitter shown in FIG. The processing speed is 50 m / min, the peripheral speed of the rotary thick blade 4 is -2.0% to + 1.0% with respect to the line speed, and the peripheral speed of the rotary thin blade 2 is- It was cut from 0.5% to -2.0%.

The total thickness of the magnetic recording tape comprising the polymer film 6, the magnetic layer 7, the protective layer 8, and the back coat 9 is 8 μm.

The increase in dropout when the magnetic recording tape in the first embodiment shown in FIG. 1 and the conventional magnetic recording tape shown in FIG. 3 were run for 500 passes on a commercially available 8 mm VTR was compared. FIG. 5 is a graph showing the relationship between the number of passes and the number of dropouts in FIG. 5. In the magnetic recording tape having a uniform slit end face 10 shown in FIG. 3, the dropout increases from around 150 passes, as indicated by the dashed line. As a result of observation with an optical microscope at this point, there is a small missing in the surface of the magnetic layer 7 at the slit end face 10. However, in the magnetic recording tape of the first embodiment shown in FIG. 1, as shown by the solid line, the dropout did not increase up to 400 passes, and the magnetic layer 7 on the slit end face 10 was not missing.

As a result of conducting the same experiment as above when the total thickness of the magnetic recording tape was 6 μm, 5 μm, and 4 μm,
Similar results were obtained. The total thickness of the magnetic recording tape is 10
In the case of μm or more, the dropout began to increase near 50 passes and was worse than the conventional magnetic recording tape. Further, when the total thickness of the magnetic recording tape exceeded 8 μm, the effect of the invention was not observed, with no change in dropout.

This is because the stiffness in the tape width direction decreases in proportion to the cube of the total thickness of the magnetic recording tape.
When the total thickness of the magnetic recording tape exceeds 8 μm, the stiffness is increased, and the vertical regulating force of the magnetic recording tape traveling system is directly applied to the convex portion 11 of the polymer film 6 on the slit end surface 10 which is the tape end surface. Convex part 11 of film 6
It is thought that the powder was scraped off and the dropout increased due to the powder.

On the other hand, when the total thickness of the magnetic recording tape is 8 μm or less, the stiffness in the tape width direction is weak, and the magnetic recording tape running system applied to the slit end face 10 by the spring effect of the projection 11 of the slit end face 10 It is probable that the vertical control force weakened.

As shown in FIG. 1, when the total thickness of the magnetic recording tape is a and the height from the tip of the projection 11 to the lower surface of the back coat 9 is b, the optimum value of the ratio is 10: When b was 7 or more, the dropout was large from the beginning, and no effect was obtained. When b was 2 or less, the effect was small.

This is considered to be dropout due to poor cutting performance and sagging of the surface of the magnetic layer 7 under the cutting condition where b is 7 or more. Also, it is considered that when b is 2 or less, the spring effect of the convex portion 11 of the slit end face 10 is small.

The projections 11 are provided on the slit end faces 10 on both sides.
The spring effect was obtained even if the slit effect was formed on one side of the slit end face 10 instead of the slit effect.

(Embodiment 2) FIG. 2 is a top view of a magnetic layer of a magnetic recording tape according to Embodiment 2 of the present invention. To explain, reference numeral 12 denotes a crack formed in the longitudinal direction of the magnetic recording tape on the upper surface of the magnetic layer 7 within 10 μm from the slit end faces 10 on both sides of the magnetic recording tape, which is the same as that of the magnetic recording tape of the second embodiment. Although the other configurations are not shown, a polymer film 6, a magnetic layer 7, a protective layer 8, and a back coat 9 are laminated as in the case of the first embodiment.

This magnetic recording tape is cut by a general disk-rotating slitter shown in FIG. 4, and the edge of the contact surface of the rotary thin blade 2 to the rotary thick blade 4 is chamfered at an angle of 10 degrees. What was used was used. The cutting conditions are as follows: the processing speed is 50 m / min, the peripheral speed of the rotary thick blade 4 is + 0.5% to + 2.0% with respect to the line speed, and the peripheral speed of the rotary thin blade 2 is relative to the rotary thick blade 4. It is cut from + 0.5% to -1.0%.

The magnetic recording tape according to the second embodiment,
A magnetic recording tape having no cracks 12 was cut by a commercially available 8 mm VTR for each tape length 60 minutes.
After running for 00 passes, the slit end face 10 and the reproduction screen were visually checked every 100 passes.

As a result, the conventional magnetic recording tape having no cracks 12 has a tape length of 30 in 200 passes.
In the vicinity of the center of the minute, one-sided extension of the slit end face 10 occurs,
Screen synchronization disorder occurred after 300 passes. In the magnetic recording tape according to the second embodiment of the present invention, no one-sided extension of the slit end face 10 occurred even after 500 passes, and no synchronization disturbance of the screen occurred.

The reason why the one-sided extension of the slit end face 10 did not occur in the magnetic recording tape according to the second embodiment in which the cracks 12 were formed was that the vertical restraining force of the magnetic recording tape traveling system applied in the tape width direction was determined by the longitudinal length of the tape. It is considered that the friction between the slit end face 10 of the magnetic recording tape and the magnetic recording tape running system was reduced due to the cushion effect of the cracks 12 formed in the direction absorbing the impact, stress and the like on the magnetic recording tape.

When the total thickness of the magnetic recording tape exceeds 8 μm, the stiffness in the tape width direction is high, and the vertical regulating force of the magnetic recording tape traveling system is directly applied to the crack 12 formed in the tape width direction, so that the crack is generated. 12, the magnetic layer 7 was destroyed, and the magnetic powder caused dropout.

The cracks 12 had a cushioning effect only by forming the cracks 12 of about 5 μm discontinuously in the width direction.

The formation of the cracks 12 provided a cushioning effect only with the slit end face 10 on one side.

Third Embodiment Next, a third embodiment of the present invention will be described. In the third embodiment, the magnetic recording has a total thickness of 8 μm or less, and has the convex portion 11 formed on the slit end face 10 in the first embodiment and the crack 12 in the tape longitudinal direction of the magnetic layer 7 in the second embodiment. It is a tape.

This magnetic recording tape was cut by a general disk-rotating slitter shown in FIG. 4, and the edge of the contact surface of the rotary thin blade 2 with the rotary thick blade 4 was chamfered at an angle of 10 degrees. What was used was used. The cutting conditions are as follows: the processing speed is 50 m / min, the peripheral speed of the rotary thick blade 4 is + 2.0% to + 1.0% with respect to the line speed, and the peripheral speed of the rotary thin blade 2 is relative to the rotary thick blade 4. It was cut from -0.5% to -2.0%.

The magnetic recording tape was run on a commercially available 8 mm VTR for 500 passes for each tape length of 60 minutes, and the dropout was measured and the slit end face 10 and the reproduction screen were visually checked every 100 passes.

As a result of this experiment, there was no increase in dropout, which was an improvement over the experimental result in the first embodiment.

This is presumably because the spring effect of the convex portion 11 of the slit end face 10 and the cushioning effect of the crack 12 in the tape width direction absorbed the vertical regulating force of the magnetic recording tape running system applied to the slit end face 10. In addition, no one-sided stretching of the magnetic recording tape occurred.

In this case, the cutting is performed under the above conditions for the blade peripheral speed and the cutting edge shape of the rotary thin blade. However, it is considered that other cutting conditions, burnishing after cutting, and the like are also possible.

[0036]

As described above, according to the present invention, the VTR
Absorbing the vertical regulating force of the magnetic recording tape running system such as VTR etc., increase of dropout due to running of the magnetic recording tape running system such as VTR in the magnetic recording tape having a total thickness of 8 μm or less, and the tape end surface which is the slit end surface. It is possible to obtain a highly durable magnetic recording tape that prevents damage such as partial elongation.

[Brief description of the drawings]

FIG. 1 is a sectional configuration diagram of a slit end surface of a magnetic recording tape according to a first embodiment of the present invention.

FIG. 2 is a top view of a magnetic layer of the magnetic recording tape according to the second embodiment of the present invention.

FIG. 3 is a sectional configuration diagram of a slit end surface of a conventional magnetic recording tape.

FIG. 4 is a configuration diagram of a disk rotating slitter.

FIG. 5 is a diagram showing the relationship between the number of passes and the number of dropouts when a magnetic recording tape is run on an 8 mm VTR.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 3 Rotating shaft 2 Rotating thin blade 4 Rotating thick blade 5 Magnetic recording tape 6 Polymer film 7 Magnetic layer 8 Protective layer 9 Back coat 10 Slit end face 11 Convex part 12 Crack

Claims (3)

[Claims] 1. A magnetic recording tape having a total thickness of 8 μm or less and a projection formed on a slit end face in a tape width direction. 2. A magnetic recording tape having a total thickness of 8 μm or less and a crack formed in a longitudinal direction of the magnetic recording tape on a magnetic layer surface within 0.5 mm from a slit end surface of the magnetic recording tape. 3. A magnetic recording tape having a total thickness of 8 μm or less and having a combination of the protrusions according to claim 1 and the cracks according to claim 2.