Radiant energy – Photocells; circuits and apparatus – Photocell controls its own optical systems
Reexamination Certificate
1999-12-08
2002-08-06
Le, Que T. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Photocell controls its own optical systems
C250S559400
Reexamination Certificate
active
06429411
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of a magnetic tape used for the record and reproduction of information. More particularly, the present invention relates to magnetic tape processing method and apparatus capable of effectively manufacturing a magnetic tape in such a manner that even if the magnetic tape is transported at a high speed in the manufacturing process and the like thereof, no slip is caused to the magnetic tape and thus the damage of the magnetic tape and the disturbance of the wound appearance thereof due to the slip can be prevented and further cupping is also reduced.
Magnetic tapes used to record and reproduce information are basically composed of a base layer which is a film such as PET (polyethylene terephthalate) and the like, a magnetic layer formed on one of the surfaces of the base layer, a backing layer formed on the surface of the base layer opposite to the magnetic layer for the purpose of improving the stability of the magnetic tape when it is transported and the strength thereof, and the like.
In the manufacturing process of the magnetic tapes, a magnetic tape (hereinafter, referred to as tape) is subjected to various types of processing such as the cutting of the tape with a slitter, the cleaning of the surface thereof with a blade edge while it is transported in the lengthwise direction thereof, made to a pancake or a cassette by being wound around a hub and delivered to the next process or to a customer. Incidentally, there is recently a tendency that tapes are transported at a high speed (transportation speed is increased), in various types of processes (manufacturing apparatus such as a blade machine, a winder and the like) for the enhancement of productivity.
The transportation of a tape is carried out by wrapping it on a capstan roller and rotating the capstan roller.
However, when the transportation speed of the tape is increased, the tape entraines air in the manufacturing apparatus such as the blade machine, slitter and the like and floats above the capstan roller and the like, whereby the tape slips and may no be normally transported.
As a result, the tape collides against or comes into improper contact with the capstan roller, a guide roller, the blade edge and the like, whereby the damage of the tape is caused such as the breakage of the tape itself or the edge thereof, the wear and peeling of the magnetic layer, and the like. Thus, a resulting tape is made improper as a product. Further, a roller for measuring a tape length (length detecting roller) is mounted on the tape manufacturing apparatus when necessary. However, when the tape slips on the length detecting roller, an error arises in the measurement of the tape length and thus a problem also arises in that the production of the tape cannot be properly managed.
Accordingly, it is difficult to increase the tape transportation speed in correspondence to the required improvement of a manufacturing efficiency in the manufacture of tape.
Further, cupping is known as another problem of magnetic tapes. Cupping is the curl of a magnetic tape in the width direction thereof and mainly caused by the difference of shrinking ratios between respective binders used in a magnetic layer and a backing layer.
Various problems are caused by the occurrence of the cupping such as the deterioration of the outside appearance of a magnetic tape as a product; the possibility of the occurrence of recording error and reading error due to the deteriorated touch of the magnetic tape against a recording head and a reading head; the lowered durability of the magnetic tape because the edges thereof are liable to be damaged, and the like.
The cupping can be improved by the methods of increasing the thickness of a magnetic layer, reducing the thickness of a backing layer, adjusting the prescription of the magnetic layer and the backing layer, and the like. However, the improvement of the cupping is limited by various kinds of problems in manufacturing process, prescription, performance capability, and the like.
More specifically, recently, the recording density of a magnetic tape has been improved. To realize the improvement, the thickness of the magnetic layer tends to be reduced. When the thickness of the backing layer is reduced accordingly for the purpose of preventing cupping, the strength of the magnetic tape is lowered and a problem arises in the durability of the tape when it is in practical use. Further, when the prescription of the magnetic layer and the backing layer is changed, the characteristics of the magnetic tape are changed and there is a possibility that a target performance capability cannot be obtained.
That is, it is a very time-consuming job to reduce the cupping by adjusting the prescription of the magnetic layer, the backing layer and the like while preventing the deterioration of the performance capability. Thus, this job is very disadvantage in the efficiency of development, the cost of the magnetic tape, and the like.
SUMMARY OF THE INVENTION
A first object of the present invention is to solve the problems of the conventional technology and to provide a magnetic tape processing method and apparatus which can efficiently manufacture a magnetic tape having excellent characteristics such that the occurrence of the slip of the magnetic tape is not caused on a capstan roller and the like, even if the transportation speed of the tape is increased in a magnetic tape manufacturing apparatus, and furthermore a size of cupping of the magnetic tape is small.
The second object of the present invention is to provide a magnetic tape processing apparatus which can manufacture efficiently the magnetic tape having the excellent characteristics described above and carry out the magnetic tape processing method described above.
The use of the magnetic tape processed by the present invention permits the magnetic tape to be precisely transported at a high speed in the magnetic tape manufacturing apparatus such as a blade machine, a winder and the like. Accordingly, a magnetic tape without damage can be stably manufactured with a high manufacturing efficiency under proper production management and further when the magnetic tape is wound and made to a winder and a pancake, the wound appearance of the magnetic tape can be made beautiful. Furthermore, the deteriorated outside appearance of the magnetic tape, the deteriorated abutment of the magnetic tape against a head, the damage of the edges of the magnetic tape, and the like due to the cupping can be also prevented.
To achieve the first object described above, the present invention provides a magnetic tape processing method characterized by comprising the steps of allowing at least one of a laser beam or laser beams in a visible region and a laser beam or laser beams in an ultraviolet region to be incident on a backing layer of a magnetic tape while transporting the magnetic tape in a lengthwise direction of the magnetic tape; and processing the backing layer by means of the laser beam or laser beams to form recesses on the backing layer.
In the magnetic tape manufacturing method of the present invention, it is preferable that the laser beam or laser beams incident on the backing layer of the magnetic tape is at least one of a plurality of laser beams which are divided and imaged by a multiple-lens, a plurality of laser beams divided by a divider and a laser beam scanned by at least one light scanning element, it is preferable that the multiple-lens is arranged such that lenses disposed in at least one of a densest state, a grid state, and one row and a plurality rows in a direction having an angle with respect to the lengthwise direction, is preferable that processing intensity of an recess formed on the backing layer is increased by forming the recess with a plurality of laser beams by overlapping optical axes of the lenses in the lengthwise direction, it is preferable that at least one of reciprocating motion of the magnetic tape in a direction perpendicular to a transporting direction of the magnetic tape, reci
Hayakawa Satoru
Inaba Hiroo
Iwasaki Osamu
Nagata Takeshi
Fuji Photo Film Co. , Ltd.
Le Que T.
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