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US 4,338,643 AGranted
Magnetic recording disc and method of making same
AssigneeFuji Photo Film Co., Ltd.
InventorEiichi Tadokoro
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AssigneeFuji Photo Film Co., Ltd.
InventorEiichi Tadokoro
Estimating the term…
In a method of making a magnetic recording sheet, a magnetic material is applied on a web in a layer consisting of a number of contiguous first strip-like zones and second strip-like zones which are alternately arranged in parallel to each other. The ratio of the width of the first strip-like zone to that of the second strip-like zone is within a range of 1:3 to 3:1. In the first strip-like zones having a width of not more than 5 mm the magnetic particles are oriented in a first direction, and in the second strip-like zones magnetic particles are oriented in a second direction which is inclined with respect to the first direction at an angle from 60.degree. to 120.degree.. With this particular orientation of the magnetic particles in the magnetic layer when the magnetic layer is applied on a web, the orientation of the magnetic particles become almost random while the magnetic layer is hardened. The magnetic recording disc thus prepared has a very low output fluctuation and a higher output level.
A method of producing a magnetic recording disc comprising applying a magnetic layer containing magnetic particles on a support film base, orienting the magnetic particles in a number of first strip-like zones in a first direction and in a number of second strip-like zones in a second direction inclined with respect to the first direction at an angle of 60.degree. to 120.degree., said first and second strip-like zones being alternately and contiguously arranged in parallel to each other, the width of each said first and second strip-like zones being not more than 5 mm and the ratio of the width of the first strip-like zone to that of the second strip-like zone being within the range of 1:3 to 3:1, solidifying the magnetic layer after the magnetic particles in said first strip-like zones, causing interaction along the boundaries between adjacent strip-like zones resulting in a random particle orientation and then stamping out a magnetic recording disc from the support film base, whereby positioning of a disc center hole is greatly fascilitated and the output is enhenced.
A magnetic recording disc comprising a circular support film base and a magnetic layer containing magnetic particles carried on a support film base wherein said magnetic layer includes a number of first strip-like zones in which the magnetic particles are oriented in a first direction and a number of second strip-like zones in which the magnetic particles are oriented in a second direction inclined with respect to the first direction at an angle of 60.degree. to 120.degree., said first and second strip-like zones being alternately and contiguously arranged in parallel to each other, the width of each said first and second strip-like zone being not more than 5 mm and the ratio of the width of the first strip-like zone to that of the second strip-like zone being within the range of 1:3 to 3:1, the magentic particles at the boundaries formed between said first and second strip-like zones being randomly oriented with said particle orientation resulting in a disc exhibiting improved recording characteristics.
Dependencies are inferred from the claim text.