Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2000-12-26
2004-10-19
Sells, James (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S281000, C156S290000, C156S308400
Reexamination Certificate
active
06805761
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a magnetic disc cartridge, and more particularly to a magnetic disc cartridge comprising a casing formed of upper and lower shell halves mated together, a disc-like recording medium supported for rotation in the casing and a pair of liners respectively fixed to the inner surfaces of the upper and lower shell halves and to a method of manufacturing the same. This invention also relates to a method of cleaning the liners.
BACKGROUND OF THE INVENTION
In a magnetic disc cartridge comprising a disc-like recording medium supported for rotation in a casing formed of upper and lower shell halves, a pair of liners formed of nonwoven fabric or the like are generally fixed to the inner surfaces of the upper and lower shell halves, respectively.
The liners are for protecting the recording medium and are formed of nonwoven fabric or the like of rayon or the like in a predetermined shape. The liners are fixed to the inner surfaces of the upper and lower shell halves by welding such as ultrasonic welding.
Each liner is generally octagonal in contour and is provided with a central opening and a slit-like cutaway portion which is opposed to the magnetic head insertion opening formed in the corresponding shell half.
When welding the liner to the shell half, a welding horn is pressed against the liner placed on the inner surface of the shell half and heat or ultrasonic vibration is applied to the welding horn, thereby fusing the inner surface of the shell half to the liner.
For example, there has been proposed in Japanese Patent Application No. 9(1997)-296838, a method of fixing a liner to the inner surface of a shell half by ultrasonic welding in which an energy director in the form of a protrusion is formed in a predetermined pattern on the inner surface of the shell half, the liner is placed on the energy director, and an ultrasonic welding horn is pressed against the liner so that the energy director is fused to the liner.
In the past, the liner is fixed to the shell half only at a part of its peripheral edge. Accordingly the non-fixed part of the peripheral edge and/or the central portion of the liner is in a floating condition and can be brought into contact with the recording medium. However, recently, as the recording capacity of the recording medium increases, it becomes necessary to rotate the recording medium at a higher speed. When the recording medium rotated at a high speed is constantly in contact with the liner, contaminants can be produced, for instance, by separation of fibers from the liner. When such contaminants adhere to the recording medium and/or the magnetic head, recording and reproducing performance can be adversely affected, recording medium driving torque can be increased, and the recording medium can wobble during rotation. Accordingly, there is a tendency to reduce contact of the liner to the recording medium.
Further since the liner is stamped out from a sheet of unwoven fabric, when the liner is not welded over its entire peripheral edge, cut fibers can drop from its peripheral edge and can adhere to the surface of the recording medium to cause drop out.
Further since the liner is formed of a hygroscopic material such as rayon, when the central portion of liner is not fixed to the inner surface of the shell half, the liner is deformed in such a manner that the central portion bulges upward due to hygroscopicity under the conditions of 60° C. in temperature and 90% in humidity. When the liner is thus deformed, the bulging portion is brought into contact with the recording medium which rotating at a high speed, which gives rise to the aforesaid problems.
SUMMARY OF THE INVENTION
In view of the foregoing observations and description, the primary object of the present invention is to provide a method of manufacturing a magnetic disc cartridge which can prevent fibers from dropping from the peripheral edges of the liners and can prevent the liners from constantly contacting with the rotating recording medium.
Another object of the present invention is to provide a method of manufacturing a magnetic disc cartridge which can prevent the central portions of the liners from bulging into contact with the recording medium even if they absorb moisture.
Still another object of the present invention is to provide a magnetic disc cartridge in which the recording medium can be effectively cleaned by the liners without substantially increasing the recording medium drive torque.
Still another object of the present invention is to provide a method of cleaning a liner of a magnetic disc cartridge which can effectively remove dust and free fibers from the liner without damaging the casing and/or the recording medium.
In accordance with a first aspect of the present invention, there is provided a method of manufacturing a magnetic disc cartridge comprising a casing formed of upper and lower shell halves mated together, a disc-like recording medium supported for rotation in the casing and an octagonal liner fixed to each of the inner surfaces of the upper and lower shell halves by use of a welding horn, the liner having a substantially octagonal outer contour defined by an outer peripheral edge, a central opening defined by an inner peripheral edge, and a slit-like cutaway portion defined by a pair of linear edges extending between the outer peripheral edge and the inner peripheral edge, which method is characterized in that
the welding horn has a welding face (the front end face) whose outer contour is an octagon conforming to the outer contour of the liner so that the liner is welded to the inner surface of the shell half substantially over the entire outer peripheral edge thereof.
It is preferred that the liner be welded to the inner surface of the shell half substantially over the entire outer peripheral edge, the inner peripheral edge and the linear edges.
The liner need not be welded to the inner surface of the shell half continuously over the edges described above but may be welded at a plurality of spots along the edges provided that the spots are sufficiently closely arranged to prevent fibers from dropping from the edges.
The liner may be welded to the inner surface of the shell half by forming an energy director protrusion on the inner surface of the shell half along the edge or edges of the liner to be welded or by forming a protrusion on the welding face of the welding horn along the edge or edges of the liner to be welded.
It is preferred that the liner be electrostatically processed to attract and hold fiber dust.
In accordance with a second aspect of the present invention, the surface of an edge portion of the liner facing the recording medium is made more distant from the recording medium than the other part of the liner and fixing agent is caused to soak into the edge portion and is solidified there.
The surface of an edge portion of the liner facing the recording medium may be made more distant from the recording medium than the other part of the liner, for instance, by forming a recess in the inner surface of the shell half or by compressing the part of the liner with the inner surface of the shell half held flat.
The fixing agent may be adhesive applied to the liner or may be molten resin obtained by fusing the shell half by applying heat or ultrasonic vibration.
In accordance with a third aspect of the present invention, there is provided a method of manufacturing a magnetic disc cartridge comprising a casing formed of upper and lower shell halves mated together, a disc-like recording medium supported for rotation in the casing and a liner fixed to each of the inner surfaces of the upper and lower shell halves by ultrasonic welding by use of an ultrasonic welding horn, the liner having an outer contour defined by an outer peripheral edge, a central opening defined by an inner peripheral edge, and a slit-like cutaway portion defined by a pair of linear edges extending between the outer peripheral edge and the inner peripheral edge, which method is characterized in that said ultrasonic welding horn is provided with a
Hayashi Yoichi
Kato Shin-ichi
Mizuta Akira
LandOfFree
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