| US 7,563,522 B2 | ||
| Magnetic recording medium | ||
| Naoto Yajima, Tokyo (Japan); Takayoshi Kuwajima, Tokyo (Japan); Akihiko Seki, Tokyo (Japan); Hiroyuki Yamada, Tokyo (Japan); and Kenichi Kitamura, Tokyo (Japan) | ||
| Assigned to TDK Corporation, Tokyo (Japan) | ||
| Filed on Nov. 02, 2006, as Appl. No. 11/555,897. | ||
| Application 11/555897 is a continuation of application No. 10/823564, filed on Apr. 14, 2004, granted, now 7,157,163. | ||
| Claims priority of application No. 2003-112472 (JP), filed on Apr. 17, 2003. | ||
| Prior Publication US 2007/0160876 A1, Jul. 12, 2007 | ||
| This patent is subject to a terminal disclaimer. | ||
| Int. Cl. G11B 5/66 (2006.01); G11B 5/64 (2006.01) | ||
| U.S. Cl. 428—839.6 [428/842.3; 360/134] | 8 Claims |
| 1. A magnetic recording medium, comprising a magnetic layer comprising at least a ferromagnetic powder and a binder resin on one surface of a non-magnetic support, wherein the thickness of the magnetic layer is within a range from 0.03 to 0.30 μm, and the number of concavities with a diameter of 10 to 60 μm and a depth of 30 nm or greater in the surface of the magnetic layer is from 0.1 concavities per 1 cm2 to 5 per 1 cm2 of surface area, and wherein the value of the average depth Rv6 of the surface of the magnetic layer, as measured by a contact type surface roughness meter, is from 5 nm to 12 nm. |