Method of inspecting magnetic recording medium, and method of controlling movement of magnetic head in magnetic recording/reproducing apparatus by utilizing inspecting method

Patent metadata

Field	Value
Publication number	US-9466323-B2
Application number	US-201113155987-A
Country	US
Kind code	B2
Filing date	Jun 8, 2011
Priority date	Jun 9, 2010
Publication date	Oct 11, 2016
Grant date	Oct 11, 2016

Abstract

A method for moving magnetic heads in a magnetic recording/reproducing apparatus, which comprises the steps of writing high-frequency signals in the magnetic recording/reproducing tracks; and then, either (i) conducting DC erasing or AC erasing to inspect extra pulse signals reproduced from the erased tracks, or (ii) inspecting concurrently occurring signals of missing pulse and spike pulse, which are reproduced from the written signals, whereby minute protrusions on a surface of the tracks were detected. Reading and writing of information are conducted while the magnetic heads are moved in a manner controlled so that reading and writing of information in specific tracks having defects is avoided. This method enhances reliability and life of the magnetic recording/reproducing apparatus.

First claim

What is claimed is:

1. An improvement in a method for inspecting a magnetic recording medium wherein prescribed signals recorded in a disk-shaped magnetic recording medium are reproduced by using magnetic heads while the disk-shaped magnetic recording medium is rotated, and the magnetic recording medium is inspected on the basis of the reproduced signals;
said improvement comprising writing high-frequency signals in magnetic recording/reproducing tracks, and then, either (i) conducting DC erasing or AC erasing to inspect extra pulse signals reproduced from the erased tracks, or (ii) inspecting concurrently occurring signals of missing pulse and spike pulse, which are reproduced from the written signals, whereby defects of the tracks are detected.

2. A process for producing a magnetic recording medium comprising a step of detecting defects of magnetic recording/reproducing tracks in a magnetic recording/reproducing apparatus; said step comprising the improvement in the method for inspecting a magnetic recording medium as claimed in claim 1 .

3. An improvement in a method for moving magnetic heads in a magnetic recording/reproducing apparatus having a plurality of concentric magnetic recording/reproducing tracks each extending in the peripheral direction, wherein reading and writing of information is conducted by moving magnetic heads while the magnetic recording medium is rotated;
said improvement comprising the steps of writing high-frequency signals in the magnetic recording/reproducing tracks; and then, either (i) conducting DC erasing or AC erasing to inspect extra pulse signals reproduced from the erased tracks, or (ii) inspecting concurrently occurring signals of missing pulse and spike pulse, which are reproduced from the written signals; writing the position information of track into a memory; and then, conducting reading and writing of information while the magnetic heads are moved in a manner controlled so that reading and writing of information in specific tracks having defects as detected by the step of either (i) or (ii) is avoided on the basis of the position information written in the memory.

4. A magnetic recording/reproducing apparatus having magnetic heads which are capable of moving by the improved method as claimed in claim 3 .

5. A magnetic recording/reproducing apparatus comprising a magnetic recording medium produced by the process as claimed in claim 2 ; a memory having written therein the reproduced signals which indicate specific magnetic recording/reproducing tracks having defects are either (i) reproduced from the DC-erased or AC-erased tracks, or (ii) concurrently occurring signals of missing pulse and spike pulse; and magnetic heads for recording and reproducing the magnetic recording medium.

6. The magnetic recording/reproducing apparatus according to claim 5 , wherein said memory having written therein the reproduced signals which indicate specific magnetic recording/reproducing tracks having defects is a memory installed in the magnetic recording medium, or is a memory independent from the magnetic recording medium.

Assignees

• Fujii Jun
• Tamura Shintaro
• Showa Denko Kk

Inventors

• Fujii Jun
• Tamura Shintaro

Classifications

• G11B2020/1826

  wherein a defect list or error map is generated · CPC title

• G11B5/024

  Erasing · CPC title

• G11B5/84 Primary

  Processes or apparatus specially adapted for manufacturing record carriers · CPC title

• G11B20/1816

  Testing · CPC title

• G11B2220/2516

  Hard disks · CPC title