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FLOPPY DISK COATING METHOD

IP.com Disclosure Number: IPCOM000062106D
Original Publication Date: 1986-Oct-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Geist, T: AUTHOR [+4]

Abstract

The wide web of flexible magnetic recording media, out of which floppy disks are to be punched, is coated by a method which allows the disk's orientation ratio (O.R.) to be controlled to a value of 1. This method is useful in coating processes which use a hydropheumatic (or membrane)-type coating head. Such coating heads, combined with certain liquid magnetic coatings, are known to result in fewer magnetic particles being oriented in the direction in which coating takes place, than are oriented in the direction normal to the coating direction. Therefore, this combination has the undesirable result of magnetic disks having an O.R. which is considerably less than 1. By measuring the web's original O.R., and providing a trailing smoothing flap, with a folded edge, of a length which is calculated as a function of this original O.R.

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FLOPPY DISK COATING METHOD

The wide web of flexible magnetic recording media, out of which floppy disks are to be punched, is coated by a method which allows the disk's orientation ratio (O.R.) to be controlled to a value of 1. This method is useful in coating processes which use a hydropheumatic (or membrane)-type coating head. Such coating heads, combined with certain liquid magnetic coatings, are known to result in fewer magnetic particles being oriented in the direction in which coating takes place, than are oriented in the direction normal to the coating direction. Therefore, this combination has the undesirable result of magnetic disks having an O.R. which is considerably less than 1. By measuring the web's original O.R., and providing a trailing smoothing flap, with a folded edge, of a length which is calculated as a function of this original O.R., the O.R. for subsequent coating can be made to be equal to 1.

U.S. Patents 4,299,186 and 4,345,543 are exemplary of coating heads of this type, and U.S. Patent 4,345,543 shows such a trailing smoothing flap. The orientation ratio of magnetic recording media is defined as the ratio of: magnetic squareness ratio in the coating direction magnetic squareness in a direction normal to the coating direction In these formulations the O.R. increases with the length of the flap. The folded edge allows a greater degree of control over a wider range of pigment loading. This method comprises the following steps: 1 - Mix a ba...