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US 6,822,827 B1Granted
Erasure techniques for magnetic tape media
AssigneeImation Corp.
InventorsJohn E. Heinz, Curtis B. Hause, Helen J. Yoo
Life of this patent
Estimating the term…
Abstract
Methods and apparatus for erasing magnetic tape are described. The tape to be erased is fed through an erasure unit that includes an array of magnetic elements. The array of magnetic elements includes a first set of magnetic elements and a second set of magnetic elements. The magnetic fields for the respective first and second sets of magnetic elements have opposite polarity, as seen by the tape as it feeds through the erasure unit. The fields seen by the tape as it feeds through the erasure unit decrease in intensity.
Claims21
A magnetic tape erasure unit comprising:
- a first set of magnetic elements,
- a second set of magnetic elements, the magnetic elements in the first and second sets positioned to define an alternating configuration, wherein the magnetic elements in the first and second sets of magnetic elements respectively produce magnetic fields of opposite polarity, and
- a set of polar elements positioned between the magnetic elements,
- wherein the magnetic elements in the first and second sets of magnetic elements produce magnetic fields of substantially equivalent intensities.
1 more element
A magnetic tape erasure unit comprising:
- a first set of magnetic elements,
- a second set of magnetic elements, the magnetic elements in the first and second sets positioned to define an alternating configuration, wherein the magnetic elements in the first and second sets of magnetic elements respectively produce magnetic fields of opposite polarity, and
- a set of polar elements positioned between the magnetic elements, wherein the polar elements comprise steel and are zinc coated.
A magnetic tape erasure unit comprising:
- a first set of magnetic elements,
- a second set of magnetic elements, the magnetic elements in the first and second sets positioned to define an alternating configuration, wherein the magnetic elements in the first and second sets of magnetic elements respectively produce magnetic fields of opposite polarity, and
- a set of polar elements positioned between the magnetic elements, wherein the polar elements define magnetic poles, and wherein the erasure unit has gaps defined by the location of the magnetic elements between the polar elements.
A magnetic tape erasure unit comprising:
- a first set of magnetic elements,
- a second set of magnetic elements, the magnetic elements in the first and second sets positioned to define an alternating configuration, wherein the magnetic elements in the first and second sets of magnetic elements respectively produce magnetic fields of opposite polarity, and
- a set of polar elements positioned between the magnetic elements, wherein the polar elements define magnetic poles, and wherein the erasure unit has gaps defined by the location of the magnetic elements between the polar elements, and
- a non-magnetic material covering the magnetic elements and filling the gaps, wherein the non-magnetic material holds the sets of magnetic elements and the polar elements in a fixed position relative to each other.
1 more element
A servo writing system comprising:
- a magnetic tape erasure unit positioned along a tape path, the erasure unit including:
- a first set of magnetic elements,
- a second set of magnetic elements, the magnetic elements in the first and second sets positioned to define an alternating configuration, wherein the magnetic elements in the first and second sets of magnetic elements respectively produce magnetic fields of opposite polarity, and
- a set of polar elements positioned between the magnetic elements, wherein the magnetic elements in the first and second sets of magnetic elements produce magnetic fields of substantially equivalent intensities;
- and
- a servo write head positioned along the tape path that writes servo tracks on the tape.
3 more elements
A method comprising:
- unspooling magnetic tape;
- passing the unspooled magnetic tape through an erasure unit to substantially demagnetize the tape;
- writing servo patterns on the unspooled and demagnetize tape;
- and
- respooling the magnetic tape.
2 more elements
A magnetic tape erasure unit comprising:
- a first set of magnetic elements,
- a second set of magnetic elements, the magnetic elements in the first and second sets positioned to define an alternating configuration, wherein the magnetic elements in the first and second sets of magnetic elements respectively produce magnetic fields of opposite polarity,
- a set of polar elements positioned between the magnetic elements, and
- a block opposite the sets of magnetic elements and the set of polar elements positioned between the magnetic elements, wherein the block defines a curve that bends away from the sets of magnetic elements and the set of polar elements positioned between the magnetic elements.
1 more element
Dependencies are inferred from the claim text.