Bulk eraser

A bulk eraser for erasing recorded information on a magnetic-recording disk in a hard-disk drive, said bulk eraser comprising:

• a first source of magnetic flux disposed opposite a second source of magnetic flux across a first portion of a gap, said first source having a first end pole disposed proximate said first portion of said gap, and said second source having a second end pole disposed proximate said first portion of said gap, wherein said first and second end poles have a same polarity;
• a first pole piece disposed on said first end pole in proximity to said first portion of said gap, said first pole piece having a first pole-tip portion;
• a second pole piece disposed on said second end pole in proximity to said first portion of said gap, said second pole piece having a second pole-tip portion;
• and
• a third pole piece disposed proximate to a second portion of said gap, said third pole piece having a third pole-tip portion;
• wherein said first pole-tip portion, said second pole-tip portion, and said third pole-tip portion define said second portion of said gap located between said first pole-tip portion, said second pole-tip portion, and said third pole-tip portion and are configured such that magnetic-flux density in said second portion of said gap lies substantially parallel to a plane of said magnetic-recording disk to erase recorded information from a portion of said magnetic-recording disk when said hard-disk drive is inserted into said second portion of said gap.

A hard-disk drive manufactured using a bulk eraser for erasing recorded information on a magnetic-recording disk in a hard-disk drive, said hard-disk drive comprising:

• a magnetic-recording disk rotatably mounted on a spindle;
• a head-gimbal assembly comprising:
• said magnetic-recording head comprising;
• a write element for writing recorded information to said magnetic-recording disk;
• and
• said read element for reading recorded information from said magnetic-recording disk
• a lead suspension attached to said magnetic-recording head;
• and
• a load beam attached at a gimbal portion of said load beam to a slider including said magnetic-recording head;
• and
• a drive motor having a drive-motor stator and a rotor, said rotor attached to said spindle for rotating said magnetic-recording disk;
• a voice-coil motor comprising:
• an armature including a voice-coil attached to said arm;
• and
• a voice-coil-motor stator including a voice-coil magnet;
• wherein said armature of said voice-coil motor is attached to said arm and is configured to move said head-arm assembly to access portions of said magnetic-recording disk;
• and
• wherein recorded information on at least one magnetic-recording disk in a disk-stack of said hard-disk drive has been erased by a bulk eraser comprising:
• a plurality of magnets;
• and
• a structure magnetically coupled with said plurality of magnets to produce magnetic-flux density in a gap, wherein said gap has a first portion, a second portion and a third portion and wherein two magnets are disposed with opposing polarity across said first portion of said gap;
• wherein said plurality of magnets and said structure are configured to produce a magnetic-flux density in said second portion of said gap sufficient to erase recorded information from a portion of at least one magnetic-recording disk in a disk-stack of said hard-disk drive when said hard-disk drive is inserted into said second portion of said gap;
• and
• wherein said plurality of magnets and said structure are configured to direct said magnetic-flux density in a substantially radial direction of said portion of said magnetic-recording disk in said hard-disk drive in said second portion of said gap.