Dynamic magnetic information storage or retrieval – Miscellaneous
Reexamination Certificate
2002-02-11
2004-03-02
Tupper, Robert S. (Department: 2652)
Dynamic magnetic information storage or retrieval
Miscellaneous
C015SDIG001
Reexamination Certificate
active
06700743
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a device for removing debris from a surface of a tape media. More particularly, it relates to an on-line or off-line tool capable of removing both loose and adherent debris from a media tape, preferably a magnetic tape, via a multi-slotted cleaning head and/or a negative pressure multi-cavity cleaning head.
Tape media, such as magnetic tape, is used for a wide variety of applications, including data storage. For data storage, servo-write applications, a very precise magnetically encoded pattern is placed on a front surface of the tape that otherwise interfaces with a magnetic or servo-writing head during use. Any debris carried by the magnetic tape (loose or more permanently adhered) can contaminate the servo-writing head, possibly disturbing a requisite spacing between the head and the tape. This, in turn, may lead to reading and/or writing errors. As such, it is highly desirable to remove as much debris as possible from the magnetic tape either during initial manufacture and/or during use. Other forms of tape media (e.g., optical tape) present similar cleaning and/or finishing concerns.
Specialized cleaning tapes have been developed that can be periodically employed to hopefully clean an otherwise contaminated head. Unfortunately, a user may forget to utilize the cleaning tape/cartridge or the cleaning tape may not effectively remove all debris. A more preferred solution is to remove debris from the magnetic tape itself prior to interaction with the head. In particular, because most unwanted debris is generated during the tape manufacturing process, a magnetic tape cleaning device is preferably implemented as part of the manufacturing process.
Currently available techniques for removing debris from magnetic tape are relatively limited and rudimentary. A first approach entails wiping the storage tape with a roughened woven or non-woven fabric. While the fabric undoubtedly removes some debris, the cleaning effects are less than complete. Alternatively, sapphire blades or scrapers are used to dislodge loose debris particles from the magnetic tape. In general terms, these sapphire-based devices are typically triangular in geometry, with each corner providing a blade-like surface(s) that scrape or abrade the magnetic tape as it wrapped about the piece. In either case, the technique is not well understood and is specifically directed toward removing loose debris only. Finally, relative to the sapphire scraper, the tool itself has been found to impart undesirable scratches or nicks onto the tape.
Conversely, some tape manufacturers employ a magnetic tape finishing process that may have some cleansing or debris removal implications. This approach of finishing magnetic tape for data storage applications entails passing the magnetic tape over an existing, but non-functioning, magnetic head. The magnetic head is selected to correspond with a particular final application, and is thus commonly referred to as a “dummy” head. The effectiveness, price, availability, and selection of these dummy heads are not well known. As a point of reference, it has been found that following 20-30 passes over a magnetic head, a newly manufactured data storage magnetic tape has lower output error rates, and is thus more “stable”. Thus, the design goal of the dummy head finishing process is to achieve a stable, low spacing and possible light asperity contact between the dummy head and the magnetic tape, but is not specifically provided to remove debris. Instead, the dummy head finishing technique attempts to impart a final “finish” to the magnetic tape, whereby any attached particles/debris slightly are polished. Notably, the previously-described fabric wiping or blade scraping techniques do not seek to replicate this beneficial stabilizing effect.
Tape media, for example magnetic tape, continues to be a highly viable tool for diverse applications, including recording and retrieving data. Though the materials used for magnetic tapes continue to evolve, the available techniques for cleaning debris from the tape and/or magnetic tape finishing operations have essentially remained unchanged. Therefore, a need exists for a cleaning tool that consistently removes both loose and more permanently attached particles, and simulates multiple passes over a magnetic head to “finish” or stabilize the magnetic tape itself.
SUMMARY OF THE INVENTION
One aspect of the present invention relates to a magnetic tape cleaning device comprising a head having a front. A plurality of transverse slots (e.g., substantially perpendicular to tape travel) are formed in the front of the head to define a plurality of spaced ridges. Each of the ridges has an outer surface extending between opposing transverse edges. With this configuration, the outer surfaces combine to define a curved, tape-receiving face. As a tape media is driven along the tape-receiving face in a generally perpendicular fashion relative to the transverse edges, the tape intimately contacts a leading transverse edge of at least three ridges. In particular, the so-contacted leading edge serves as a scraping or cutting surface relative to the direction of tape travel. This intimate contact effectuates removal of debris. In one preferred embodiment, the head includes at least ten of the transverse slots, each having a depth in the range of 0.005-0.02 inch. In another preferred embodiment, the outer surfaces of the ridges combine to define a uniform radius of curvature in the range of 5-20 mm.
Another aspect of the present invention relates to a method of removing debris from a tape media. The method includes providing a cleaning head having a front and a plurality of transverse slots formed in the front. The slots define a plurality of spaced ridges each having an outer surface extending between opposing transverse edges. Further, the outer surfaces combine to define a curved, tape-receiving face. The tape is driven across the face in a generally perpendicular fashion relative to the transverse edges such that a transverse chordal segment of the tape intimately contacts a leading transverse edge of at least three of the ridges with the leading edge of each ridge being defined by the direction of tape travel. This driven contact between the tape and the transverse edges results in debris being removed from the tape. In one preferred embodiment, the method of removing debris is performed within a data storage tape cartridge. In another preferred embodiment, the method of removing debris is performed as part of a magnetic tape manufacturing process.
Yet another aspect of the present invention relates to a tape media cleaning device comprising a head defined by opposing outer regions and a central region. A plurality of transverse cavities are formed in the front to define a plurality of lands in the central region. Each of the lands has an outer face extending between opposing sides, with opposing corners being formed at an intersection between the outer face and the opposing sides, respectively. Further, the head includes first and second outriggers formed at the opposing outer regions, respectively. In this regard, each of the outriggers are spaced from a corresponding, adjacent land. With the above construction, the plurality of cavities are configured to establish a sub-ambient condition as a tape is driven across the outer faces in a generally perpendicular fashion relative to the lands. As a result, the tape at least partially wraps about a leading corner of at least three of the lands, thereby effectuating removal of debris. In one preferred embodiment, the head includes at least four of the lands. In another preferred embodiment, the plurality of cavities includes opposing outer cavities separating the respective outriggers from an adjacent one of the lands, along with central cavities separating the lands and adapted to generate the intended negative pressure effect. With this in mind, each of the central cavities preferably has a depth in the range of 1-10 microns. In another preferred embodiment, the clea
Fahimi Saeed A.
Jewett Richard E.
Markert Allan R.
Richards Durkee B.
Imation Corp.
Levinson Eric D.
Tupper Robert S.
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