Dynamic magnetic information storage or retrieval – Record medium – In container
Reexamination Certificate
1999-03-12
2001-11-13
Klimowicz, William (Department: 2652)
Dynamic magnetic information storage or retrieval
Record medium
In container
C369S291100
Reexamination Certificate
active
06317292
ABSTRACT:
BACKGROUND
1. Field of the Invention
The present invention relates to disk cartridges for storing electronic information, and more particularly, to a disk cartridge having a spun fabric liner.
2. Description of the Prior Art
Removable disk cartridges for storing digital electronic information typically comprise an outer casing or shell that houses a magnetic, magneto-optical or optical disk upon which electronic information can be stored. The cartridge shell often comprises upper and lower halves that are joined together to house the disk. The disk is mounted on a hub that rotates freely within the cartridge. When the cartridge is inserted into a disk drive, a spindle motor in the drive engages with the disk hub in order to rotate the disk within the cartridge at a given speed. The outer shell of the cartridge typically has an aperture near one edge to provide the recording heads of the drive with access to the disk. A shutter or door mechanism is often provided to cover the aperture when the cartridge is not in use to prevent dust or other contaminants from entering the cartridge and settling on the recording surface of the disk.
Although the cartridge shell and shutter mechanism provide some protection against contaminants entering the cartridge, some contaminants will inevitably reach the recording surface of the disk. For example, dust, smoke and other debris may enter the cartridge through the disk hub or through the cartridge shutter when the disk is inserted in a disk drive. Additionally, magnetic particles may be generated during manufacturing of the disk cartridge as well as during read/write operations in the disk drive. These contaminants can interfere with a read/write head causing errors and a potential loss of information.
To reduce the risk of read/write errors resulting from particles on the disk surface, cartridges often include one or more fabric liners within the cartridge placed in contact with the disk surface. These liners typically are formed of a mixture of non-woven fibers bonded together either thermally, with an adhesive binder, or through a hydroentangling process such as that described in U.S. Pat. No. 5,311,389.
As illustrated in U.S. Pat. Nos. 4,750,075, 5,006,948, 5,083,231 and 5,216,566, the fabric liners are typically affixed to the upper and lower halves of the cartridge shell between so that they lie in a plane above the respective surfaces of the disk. In each of these examples, lifters and opposing ribs are provided on the inner surfaces of the upper and lower shells to bring the fabric liners into contact with at least a portion of the disk surface. Essentially, the lifters and ribs cooperate to force the liners against the disk surface. While the use of lifters and/or ribs ensures that the fabric liner contacts the disk surface and wipes unwanted particles from the disk, the force with which the liners are pressed against the disk creates a significant amount of drag on the disk as it rotates within the cartridge. Increased drag requires a corresponding increase in the strength of the disk drive spindle motor. Additionally, the increased contact pressure between the liners and the disk increases wear on the disk surface.
As flexible media products have evolved the thickness of the magnetic recording layer has become progressively thinner. For example, the 1.44 MB floppy disk has a magnetic coating layer of about 2 microns thick. The 100 MB Zip™ disk has a magnetic coating layer which is about 0.4 microns thick, while the present generation Zip™ 250 disk has a thickness of about 0.24 microns. The Zip™ 250 disk is shown, for example, in application Ser. No. 09/161,007, filed Sep. 25, 1998.
Future generation flexible products are intended to have a magnetic coating thickness of about 0.15 microns or less. It can be seen from this progression of thinner and thinner magnetic coating layers that the task of wiping the media free of air suspended debris while at the same time not damaging the ever thinner magnetic coating is quite challenging.
Historically, non-woven fabrics made of cotton, polyester, rayon, nylon, polypropylene, cellulose and other low cost fibers have been used to wipe the surfaces of flexible media. In a typical floppy disk application, the liner is brought into contact with the flexible media surface through means of a lifter. Other methods include a fuzzed liner region where upstanding fibers were generated during the cartridge manufacturing process to contact the media surface. The ideal wiper is aggressive with its debris wiping action while at the same time being gentle in its physical interaction with the underlying thin magnetic coating. The fibers must not break easily and become a source of debris themselves. Also, a fiber which minimizes the wicking up of the media's lubricant in the process of wiping is of significant importance.
Accordingly, there is a need for a removable disk cartridge having a liner that provides adequate wiping of the disk to remove unwanted particles, that creates much less drag on the disk and does not damage the magnetic coating. The liner should also be low cost and easy to manufacture. The present invention satisfies these needs.
SUMMARY OF THE INVENTION
The present invention is directed to a disk cartridge having a non-woven liner of PTFE fibers. The disk cartridge comprises a rotatable disk having upper and lower surfaces and an outer casing for rotatably housing the disk. The casing comprises upper and lower shells that mate to form the casing. Each of the upper and lower shells has an inner surface disposed in facing relation to a respective surface of the disk. The cartridge has a head access opening on its front peripheral edge, and the upper and lower shells have grooves formed therein to provide sufficient space for the magnetic heads of a disk drive to move across the surface of the disk. A spun non-woven fabric liner comprising a plurality of PTFE fibers is attached to the inner surface of one of the upper and lower shells. A main body of the fabric liner lies against the inner surface of the shell and is spaced a predetermined distance from the corresponding surface of the disk. According to one embodiment of the present invention, a region of the fabric liner is subjected to a fuzzing process in which the bonded fibers in that region are loosened to form a region of upstanding fibers that extend from the main body of the liner to the surface of the disk. The fibers wipe the surface of the disk while the main body of the liner remains spaced from the disk thereby reducing drag. In a preferred embodiment, a second non-woven fabric liner is attached to the inner surface of the other of shells.
Preferably, the spacing between the main body of the fabric liner and the recording surface of the disk is in the range of about 0.2 to 0.8 mm. The spun non-woven liner preferably is attached to the inner surface of the shell by an adhesive. Additionally, the inner surfaces of the upper and lower shells preferably are substantially planar.
Additional features and advantages of the present invention will become evident hereinafter.
REFERENCES:
patent: 3311960 (1967-04-01), Kessler
patent: 3719537 (1973-03-01), Wilcox
patent: 4392170 (1983-07-01), Okada
patent: 4586606 (1986-05-01), Howey
patent: 4610352 (1986-09-01), Howey et al.
patent: 4648002 (1987-03-01), Mroz et al.
patent: 4680661 (1987-07-01), Oishi
patent: 4695912 (1987-09-01), Moriwaki
patent: 4699268 (1987-10-01), Oishi
patent: 4750075 (1988-06-01), Oishi
patent: 4782417 (1988-11-01), Tanaka et al.
patent: 4791516 (1988-12-01), Seto
patent: 4802049 (1989-01-01), Tanaka et al.
patent: 4812938 (1989-03-01), Rogers et al.
patent: 4864451 (1989-09-01), Iwasa et al.
patent: 4977475 (1990-12-01), Shiba et al.
patent: 5006948 (1991-04-01), Fukunaga et al.
patent: 5060105 (1991-10-01), Howey
patent: 5083231 (1992-01-01), Veenstra et al.
patent: 5115961 (1992-05-01), Nakajima
patent: 5122919 (1992-06-01), Takemae et al.
patent: 5179487 (1993-01-01), Niitsuma et al.
patent: 5189585 (1993-02-01), Kubo
patent: 5216566 (1993-06-01), Ob
Ma Yiping
Thomas, III Fred C.
Iomega Corporation
Klimowicz William
Woodcock Washburn Kurtz Mackiewicz & Norris LLP
LandOfFree
PTFE fiber based liner for flexible high density magnetic media does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with PTFE fiber based liner for flexible high density magnetic media, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and PTFE fiber based liner for flexible high density magnetic media will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2572451