Dynamic information storage or retrieval – Storage medium structure – Adjuncts or adapters
Reexamination Certificate
1996-06-18
2001-07-24
Ometz, David L. (Department: 2652)
Dynamic information storage or retrieval
Storage medium structure
Adjuncts or adapters
C360S133000
Reexamination Certificate
active
06266319
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a disc cartridge and a molding die therefor, and more particularly to a disc cartridge having a disc-like medium such as an optical disc, a magneto-optical disc or the like rotatably received therein and a molding die therefor.
In general, an information medium or a disc-like medium such as, for example, a magnetic disc, an optical disc, a magneto-optical disc or the like is used in the form of a disc cartridge while being received in a casing. Conventional casings for such a disc cartridge include a casing made of one kind of transparent or non-transparent resin and a casing integrally made of both transparent resin and non-transparent resin. Such a transparent disc cartridge is disclosed in Japanese Patent Application Laid-Open Publication No. 325494/1993 and Japanese Utility Model Application Laid-Open Publication No. 52064/1994 and such a non-transparent disc cartridge is conventionally used for a micro floppy disc (MFD). The assignee proposed a disc cartridge integrally formed of both non-transparent resin and transparent resin, as disclosed in Japanese Utility Model Application No. 17002/1994 and Japanese Patent Application No. 337509/1994.
Of the above-described conventional casings for the disc cartridge, the casing made of one kind of non-transparent resin or transparent or semitransparent resin is monotonous in design. This is remarkable particularly when it is made of non-transparent resin. Thus, it is difficult for a user to distinguish between non-transparent disc cartridges manufactured by different manufacturers. Also, the conventional casing made of transparent resin causes an internal structure of the disc cartridge to be observed from outside, therefore, it is required to design the disc cartridge while taking a serious view of an appearance thereof. Unfortunately, this renders manufacturing of the cartridge highly troublesome and increases a manufacturing cost thereof.
The casing integrally made of both non-transparent resin and transparent resin causes a joining surface between the non-transparent resin and the transparent resin to be disadvantageously reduced in thickness because the casing generally has a thickness as small as about 1 mm. In order to provide joining strength of a sufficient level, it is required to carry out charging of two kinds of resins prior to solidification of the resins. This requires to increase both a resin temperature and a die temperature to an increase level, leading to a deterioration in workability and a failure in molding called burns.
Also, a conventional molding die for forming conventional non-transparent resin and transparent resin into a casing is so constructed that a slide mold is arranged in a movable part of the molding die in a manner to be closely contacted with a surface of the die opposite thereto, to thereby prevent the non-transparent resin from mixedly entering a portion of the casing made of the transparent resin. The non-transparent resin is first charged in the die thus constructed, resulting in a peripheral body of a casing being formed. Then, the slide mold is retreated to form a space in the die, which is charged with the transparent resin to form a transparent window. In a conventional tape cassette, a casing is often constructed in such a manner that non-transparent resin and transparent or semitransparent resin are integrally molded into two-layer structure having a non-transparent resin layer and a transparent or semitransparent resin layer laminated on each other in a direction of thickness of the casing. In the tape cassette thus constructed, the casing has a thickness of about 1.8 mm and a sheet material of PET is interposed between a tape-like medium received therein and an inner surface of the casing, so that the casing exhibits joining strength of an enough level even if it is not formed into the two-layer structure and a joining surface is provided only in the direction of thickness of the casing. Also, the sheet effectively prevents any bur possibly formed on the casing from adversely affecting the tape-like medium. Whereas, in the conventional disc cartridge, the transparent window of the casing is generally arranged so as to be opposite to a disc-like medium and a boundary between the slide mold and the movable part causes a bur to be formed on the transparent window of the casing. Unfortunately, the bur contacts with the disc-like medium to damage a recording and reproducing surface of the medium due to lack of any sheet therebetween.
SUMMARY OF THE INVENTION
The present invention has been made in view of the foregoing disadvantages of the prior art.
Accordingly, it is an object of the present invention to provide a disc cartridge which is capable of improving an appearance of the disc cartridge and quality thereof.
It is another object of the present invention to provide a disc cartridge which is capable of significantly improving moldability of a casing integrally made of both non-transparent resin and transparent or semitransparent resin.
It is a further object of the present invention to provide a disc cartridge which is capable of providing a casing with increased strength and increasing reliability thereof.
It is still another object of the present invention to provide a molding die which is capable of satisfactorily providing a disc cartridge exhibiting such advantages as described above.
In accordance with one aspect of the present invention, a disc cartridge is provided. The disc cartridge includes a casing of a substantially rectangular shape formed with at least one opening through which a drive and/or operation element of a recording and reproducing unit is withdrawably inserted into the casing. The casing is integrally formed of non-transparent resin and transparent or semitransparent resin. The casing is formed therein with a disc receiving section in which a disc-like medium is rotatably received. The casing is provided at a peripheral area thereof other than the disc receiving section opposite to the disc-like medium with a two-layer section constructed of a non-transparent resin layer and a transparent or semitransparent resin layer laminated on each other in a direction of thickness of the casing.
In a preferred embodiment of the present invention, the disc receiving section of the casing has a transparent window formed of transparent or semitransparent resin. The transparent window is formed so as to be contiguous to said two-layer section.
In a preferred embodiment of the present invention, the disc receiving section is formed without leaving a parting line of a casing molding die thereon.
In a preferred embodiment of the present invention, the non-transparent resin layer of the two-layer section is arranged on a side of an inner surface of the casing and the transparent or semitransparent resin layer thereof is arranged on a side of an outer surface of the casing.
In accordance with another aspect of the present invention, a molding die for a disc cartridge is provided. The molding die includes a fixed part and a movable part for integrally molding non-transparent resin and transparent or semitransparent resin into a casing for a disc cartridge. The casing includes a transparent resin section and a two-layer section consisting of at least a transparent resin layer. The molding die also includes a slide mold for molding the transparent resin section and the transparent resin layer of the two-layer section. The slid mold is arranged in the fixed part.
REFERENCES:
patent: 5101307 (1992-03-01), Mizuno et al.
patent: 3-162787 (1991-07-01), None
patent: 5-325494 (1993-12-01), None
patent: 6-52064 (1994-07-01), None
patent: 3013199 (1995-04-01), None
Ikebe Masaru
Miyazaki Yukio
Momoi Akio
Lerner David Littenberg Krumholz & Mentlik LLP
Ometz David L.
TDK Corporation
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