Magnetic recording heat which accurately defines the width of the recording track

Claim 2

A magnetic recording head comprising means for magnetizing an area of an adjacent magnetic storage medium by a first portion of said recording head of a first predetermined width, means integrally associated with a second portion of said recording head of a second predetermined width greater than said first predetermined width for reducing the width of the magnetized area to a width less than said first predetermined width, said width reducing means including the lower portion of a surface of a magnetic core of said second predetermined width facing an erase gap in said second portion, said lower portion having a notch therein facing said erase gap, said notch being of sufficient depth into the magnetic core to eliminate the erasing capability of that portion of the erase gap opposite thereto, said notch having a width less than said first predetermined width whereby magnetically recorded areas between each end of said notch and the lateral ends of said erase gap adjacent thereto will be erased upon energization of said width reducing means.

Claim 3

The magnetic recording head of claim 1 wherein said magnetizing means in said first portion of said notch in said second portion are symmetrically positioned with respect to the longitudinal axis of said magnetic recording head.

Claim 4

The magnetic recording head of claim 1 further including pre-erase means associated with a third portion of said recording head, said pre-erase means having a width at least equal to the width of said magnetizing means in said first portion, said pre-erase means adapted to bring portions of said magnetic recording medium adjacent thereto to a substantially uniform condition prior to the recording thereon of information by said magnetizing means.

Claim 5

A magnetic recording head comprising a central magnetic core having a plurality of legs, a read-write coil disposed about a first leg, an erase coil disposed about a second leg, the end of each of said legs adjacent the lower portion of said magnetic core being slightly spaced from said magnetic core to respectively define a read-write gap and an erase gap, said first leg having a first predetermined width less than the width of said magnetic core thereby defining said read write gap, that portion of the surface of said magnetic core facing said erase gap being of a predetermined width greater than the width of said read-write gap and having a notch therein, said notch being of sufficient depth into said magnetic core to eliminate the erasing capability of that portion of said erase gap opposite thereto whereby, upon energization of said read-write coil when said read-write gap is positioned adjacent a magnetic storage medium, a data area of said first predetermined width is magnetically recorded thereon and, as said magnetized data area of said first predetermined width is positioned adjacent said erase gap and upon energization of said erase coil, the width of said magnetized data area is reduced to the smaller width of said notch by erasure of those magnetized areas between each end of said notch and the lateral ends of said erasure gap adjacent thereto.

Claim 6

A magnetic recording head comprising a central magnetic core having a plurality of legs, a read-write coil disposed about a first leg, an erase coil disposed about a second leg, the end of each of said legs adjacent the lower portion of said magnetic core being slightly spaced from said magnetic core to respectively define a read-write gap and an erase gap, said first leg having a first predetermined width less than the width of said magnetic core thereby defining said read write gap, that portion of the surface of said magnetic core facing said erase gap being of a predetermined width greater than the width of said read-write gap and having a notch therein, said notch being of sufficient depth into said magnetic core to eliminate the erasing capability of that portion of said erase gap opposite thereto whereby, upon energization of said read-write coil when said read-write gap is positioned adjacent a magnetic storage medium, a data area of said first predetermined width is magnetically recorded thereon and, as said magnetized data area of said first predetermined width is positioned adjacent said erase gap and upon energization of said erase coil, the width of said magnetized data area is reduced to the smaller width of said notch by erasure of those magnetized areas between each end of said notch and the lateral ends of said erasure gap adjacent thereto.

Claim 7

The magnetic recording head of claim 4 wherein said read-write gap and said notch are symmetrIcally positioned with respect to the longitudinal axis of said magnetic recording head.

Claim 8

The magnetic recording head of claim 5 wherein said read-write gap is about 4 mils wide and said notch is about 3 mils wide.

Claim 9

The magnetic recording head of claim 4 wherein the depth of said notch is at least 10 times the depth of said erase gap, the depth of said erase gap being determined by the distance between said surface of said magnetic core having said notch therein and that surface of said end of said erase leg opposite therefrom.

Claim 10

The magnetic recording head of claim 4 further including a non-magnetic spacer within said read-write gap and a non-magnetic spacer within said erase gap.

Claim 11

The magnetic recording head of claim 4 wherein said central magnetic core and said plurality of legs are formed from a single unitary magnetic piece.

Claim 12

The magnetic recording head of claim 4 wherein each of said plurality of legs is a separate piece from said central magnetic core.

Claim 13

The magnetic recording head of claim 4 further including a pre-erase leg having a pre-erase coil disposed thereabout, said pre-erase leg positioned on the opposite side of said read-write leg from said central magnetic core, the end of said pre-erase leg adjacent the lower portion of said read-write leg being slightly spaced therefrom to define a pre-erase gap having a width at least equal to the width of said read-write gap whereby, upon energization of said pre-erase coil when said pre-erase gap is positioned adjacent a magnetic storage medium, the adjacent portions of said magnetic storage medium are brought to a substantially uniform state prior to the magnetic recording thereon of said data area of said first width.

Claim 14

The magnetic recording head of claim 11 further including a non-magnetic spacer within each of said pre-erase, read-write and erase gaps.

Claim 15

The magnetic recording head of claim 11 wherein each of said plurality of legs is a separate piece from said central magnetic core.

Claim 16

A magnetic recording head comprising a central magnetic core, a first substantially U-shaped leg disposed with the ends thereof adjacent a first surface of said magnetic core, the end of said first substantially U-shaped leg adjacent the lower portion of said first surface being slightly spaced therefrom to define a read-write gap, a second substantially U-shaped leg disposed with the ends thereof adjacent that surface of said magnetic core parallel to said first surface, the end of said second substantially U-shaped leg adjacent the lower portion of said magnetic core being slightly spaced therefrom to define an erase gap, said first substantially U-shaped leg being of a first predetermined width less than the width of said magnetic core thereby defining said read-write gap, said second substantially U-shaped leg being of a width greater than the width of said read-write gap thereby defining said erase gap, the surface of said magnetic core facing said erase gap having a notch in the lower portion thereof, said notch being of a width less than the width of said read-write gap, said notch being of sufficient depth into said magnetic core to eliminate the erasing capability of that portion of said erase gap opposite thereto.

Claim 17

A magnetic recording head comprising a central magnetic core, a first substantially U-shaped leg disposed with the ends thereof adjacent a first surface of said magnetic core, the end of said first substantially U-shaped leg adjacent the lower portion of said first surface being slightly spaced therefrom to define a read-write gap, a second substantially U-shaped leg disposed with the ends thereof adjacent that surface of said magnetic core parallel to said first surface, the end of said second substantially U-shaped leg adjacent the lower portion of said magnetic core being slightly spaced therefrom to define an erase gap, said first substantially U-shaped leg being of a first predetermined width less than the width of said magnetic core thereby defining said read-write gap, said second substantially U-shaped leg being of a width greater than the width of said read-write gap thereby defining said erase gap, the surface of said magnetic core facing said erase gap having a notch in the lower portion thereof, said notch being of a width less than the width of said read-write gap, said notch being of sufficient depth into said magnetic core to eliminate the erasing capability of that portion of said erase gap opposite thereto.

Claim 18

The magnetic recording head of claim 14 further including a read-write coil disposed about said first substantially U-shaped leg, an erase coil disposed about said second substantially U-shaped leg, means to cause relative movement of said magnetic recording head and a magnetic storage medium positioned adjacent thereto, means to energize said read-write coil to magnetize an area on said magnetic storage medium, said magnetized area having a width substantially equaL to the width of said read-write gap, and means to energize said erase coil when said erase gap is positioned adjacent said magnetized area whereby those portions of said magnetized area between each end of said notch and the lateral end of said erase gap adjacent thereTo are erased such that the width of said magnetized area is reduced substantially to the width of said notch.

Claim 19

The magnetic recording head of claim 14 wherein said read-write gap and said notch are symmetrically positioned with respect to the longitudinal axis of said magnetic recording head.

Claim 20

The magnetic recording head of claim 14 wherein said read-write gap is about 4 mils wide and said notch is about 3 mils wide.

Claim 21

The magnetic recording head of claim 14 wherein the depth of said notch is at least 10 times the depth of said erase gap, the depth of said erase gap being determined by the distance between said surface of said magnetic core having said notch therein and that surface of said end of said erase leg opposite therefrom.

Claim 22

The magnetic recording head of claim 14 wherein each of said first and second substantially U-shaped legs are formed from pieces distinct from said central magnetic core.

Claim 23

The magnetic recording head of claim 14 further including a third substantially U-shaped leg positioned on the opposite side of said read-write leg from said central magnetic core, the end of said third substantially U-shaped leg adjacent the lower portion of said read-write leg being slightly spaced therefrom to define a pre-erase gap, said pre-erase gap having a width at least equal to the width of said read-write gap.

Claim 24

The magnetic recording head of claim 20 further including a read-write coil disposed about said first substantially U-shaped leg, an erase coil disposed about said second substantially U-shaped leg, a pre-erase coil disposed about said third substantially U-shaped leg, means to cause relative movement of said magnetic recording head and a magnetic storage medium positioned adjacent thereto, means to energize said pre-erase coil to magnetize portions of said magnetic recording medium adjacent to said pre-erase gap to a substantially uniform condition, means to energize said read-write coil to magnetize an area in said conditioned portion of said magnetic storage medium to a first width substantially equal to the width of said read-write gap, and means to energize said erase coil when said erase gap is positioned adjacent said magnetized area whereby those portions of said magnetized area between each end of said notch and the lateral ends of said erase gap adjacent thereto are erased such that the width of said magnetized area is reduced substantially to the width of said notch.

Claim 25

The magnetic recording head of claim 20 wherein each of said first, second, and third substantially U-shaped legs are formed from pieces distinct from said central magnetic core.